Detention has become an undeniably central part of immigration enforcement today.1 In principle, the constitutional right to be free from deprivation of “life, liberty, or property, without due process of law”2 extends to all “persons” within U.S. territory, regardless of citizenship.3 In practice, due process for noncitizen detainees tends to be far more circumscribed.4 Against this background, hundreds of immigrant detainees across the nation filed lawsuits during the COVID-19 pandemic, claiming that continued confinement in overcrowded and inadequate conditions amounted to a violation of their constitutional due process rights.5 The litigation has forced courts to directly confront a critical issue that affects thousands, yet remains obscured by a lack of judicial guidance: the extent of substantive due process protection that the government owes to noncitizens held in its custody.
This Note analyzes this recent development and its wider implications. The discussion proceeds in three stages. Part I explains the theoretical background for constitutional challenges by noncitizens and describes the two competing frameworks that govern such claims. The first is the plenary power doctrine, under which courts grant special deference to political branches over decisions to admit or exclude noncitizens.6 The second is the “aliens’ rights tradition,” characterized by a line of cases that apply heightened scrutiny to government action and affirm the status of noncitizens as “persons” protected under the Constitution.7 As scholars have previously observed, the two frameworks are meant to govern separate spheres, but the boundary is not always clear.8 Part II turns to the specific context of substantive due process claims in immigration detention, particularly those cases that challenge the conditions of detention facilities or deprivations and mistreatment therein. As will be shown, cases addressing these claims reflect inconsistencies among courts. Part III describes the recent litigation arising from the COVID-19 pandemic. While recognizing that the fact-specific nature of the lawsuits limits their precedential value, this Note argues that the decisions collectively shift the emphasis away from the logic of judicial deference toward a recognition of the government’s affirmative duty to protect and provide care for immigrant detainees.
I. Constitutional Challenges by Noncitizens
Since its foundational cases, the Court has adopted two contrasting approaches to the rights and obligations of noncitizens.9 Under the plenary power doctrine, it has long recognized that, as a matter of sovereign prerogative, political branches have broad and near-exclusive authority over immigration law governing the admission and exclusion of noncitizens.10 This heightened judicial deference developed alongside a competing “aliens’ rights tradition,” which extends constitutional protections to noncitizens in matters unrelated to their admission and exclusion.11 This Part summarizes the development of these two frameworks and discusses the limits of the plenary power–aliens’ rights distinction.
A. Development of the Competing Frameworks
1. Plenary Power Doctrine. — The plenary power doctrine can be traced back to the Chinese Exclusion Case,12 which involved a noncitizen laborer who temporarily left the United States with a certificate permitting his return.13 After his departure, Congress declared the certificate void, effectively barring his reentry.14 The Court upheld this action, noting that the federal government enjoys considerable independence and discretion to exclude foreigners.15 Fong Yue Ting v. United States16 extended this deference to the power to expel, by allowing Congress to deport Chinese laborers who lacked a certificate of residence and failed to prove their lawful status by testimony of a “credible white witness.”17 The full breadth of the plenary power doctrine was demonstrated in a series of 1950s cases. United States ex rel. Knauff v. Shaughnessy18 first held that the wife of a U.S. citizen could be “permanently excluded without a hearing”19 solely based on a finding that “her admission would be prejudicial to the interests of the United States.”20 In so doing, the Court infamously declared that, with regard to noncitizens seeking admission, “[w]hatever the procedure authorized by Congress is, it is due process.”21 Shaughnessy v. United States ex rel. Mezei22 expanded upon Knauff by upholding the exclusion and detention of a long-term permanent resident returning from a trip abroad.23
The Court has since qualified the plenary power doctrine and alleviated its harshest effects in important ways.24 Nonetheless, its early decisions continue to provide a “century of precedent” in favor of the government’s broad discretion to expel or exclude,25 on the basis of which protections for noncitizens have been significantly curtailed. Most recently, in 2018, Trump v. Hawaii26 confirmed the endurance of the doctrine, with the majority applying a highly deferential standard of review to uphold a controversial travel ban despite allegations of discriminatory intent against Muslim immigrants and Islam.27
2. The Aliens’ Rights Tradition. — The early plenary power cases were accompanied by sharply worded and powerful dissents.28 The dissenters highlighted the need for a limiting principle, cautioning that the doctrine’s sweeping scope “might . . . sanction[] . . . the most shocking brutality conceivable” toward noncitizens.29 This concern gave rise to court decisions establishing that outside of immigration law, noncitizens are entitled to constitutional rights, which in turn place constraints on state action.30 The earliest of such cases, Yick Wo v. Hopkins31 upheld a noncitizen’s challenge to the discriminatory enforcement of a municipal ordinance, reasoning that the equal protection of laws under the Fourteenth Amendment is “universal in [its] application, to all persons within the territorial jurisdiction.”32 Wong Wing v. United States33 extended this principle to the Fifth and Sixth Amendments, stressing that while Congress had broad power to exclude and expel noncitizens, it lacked authority to sentence them to “imprisonment at hard labor” prior to removal.34 Since the latter “inflicts an infamous punishment,” it triggered judicial scrutiny for compliance with constitutional constraints of criminal procedure.35 In other words, the “punishment” of hard labor removed the case from the domain of immigration law to that of criminal law, where special judicial deference was not warranted.36
B. Limits of the Distinction
The plenary power–aliens’ rights distinction thus turns on whether the subject matter in controversy lies within or beyond the scope of immigration law. Subsequent cases have challenged this dichotomy, however, with some scaling back the government’s plenary power in the immigration context, and others restricting noncitizens’ rights in the nonimmigration context.37 Notably, Landon v. Plasencia38 narrowed the Court’s holding in Mezei by finding that permanent residents who briefly left the country were entitled to greater procedural due process protection in their exclusion hearings.39 The Court reasoned that “once an alien gains admission to our country and begins to develop . . . ties[,] . . . his constitutional status changes accordingly.”40
If Landon exemplifies a divergence from the strict application of the plenary power doctrine, United States v. Verdugo-Urquidez41 may suggest a deviation from the aliens’ rights tradition.42 In Verdugo-Urquidez, the noncitizen-plaintiff sought to suppress evidence seized by federal agents from his Mexican residence while he remained incarcerated in the United States pending his criminal proceeding.43 Rejecting this claim, the Court held that the Fourth Amendment does not extend to extraterritorial searches, adding that reliance on aliens’ rights tradition cases such as Yick Wo and Wong Wing would be misplaced, as the plaintiff “had no previous significant voluntary connection with the United States.”44
As both cases demonstrate, while the competing frameworks are meant to govern distinct realms, they often bleed into each other in seemingly inconsistent ways.45 In light of this difficulty, critics have offered a variety of alternative theories.46 One such theory focuses on “membership” or “community ties,” broadly suggesting that noncitizens who have developed more connections with American society are entitled to greater due process.47 In contrast, the “municipal law approach” focuses less on noncitizens’ physical location or voluntary ties with the country and instead posits that constitutional rights may extend to noncitizens by virtue of them being required to comply with U.S. laws.48
II. Substantive Due Process in Immigration Detention
A. Unsettled Questions
While the Court has recognized that both procedural and substantive due process challenges are available in the context of immigration detention,49 the contours remain unsettled. One possible explanation for this uncertainty is the previously described “porous border between the plenary power doctrine and the aliens’ rights tradition.”50 In immigration detention cases, courts are asked to separate the nature of the constitutional complaint from the “underlying predicate” of immigration detention;51 this may be particularly complex when the remedy sought — whether that be parole into the country or relief from removal — seemingly interferes with the government’s control over immigration.52 Additional sources of ambiguity are the lack of definitive judicial guidance and the Court’s sidestepping of constitutional questions, even for more frequently litigated issues such as the durational limits on detention.53
Of the various substantive due process issues related to immigration detention, this Note focuses on challenges to conditions of confinement and the deprivations and mistreatment therein. While these are separate claims, they are related in the sense that they all implicate the government’s duty under the Constitution to protect and provide for individuals under certain circumstances.54 Such claims warrant more attention than they currently receive, especially in light of the growing salience of constitutional claims in immigration law.55
In 1995, Professor Margaret Taylor observed that “[o]nly a handful of reported cases have decided the due process challenges to conditions of confinement suffered by alien detainees,” and even those “reflect[ed] confusion over which of the two competing lines of cases — the plenary power doctrine or the aliens’ rights tradition — should govern.”56 More than two decades later, the problem persists. Such claims are often resolved through settlement agreements or consent decrees — as was the case in Reno v. Flores.57 There is also no federal statute that explicitly sets forth the standard for conditions of immigration detention.58 And while U.S. Immigration and Customs Enforcement (ICE) has published nationwide detention standards,59 these are implemented through individually negotiated contracts, leading to varying degrees of protection across detention facilities.60
In the absence of clear judicial and statutory guidance, lower courts addressing constitutional challenges to immigration detention have looked to the case law governing similar claims by prisoners and pretrial detainees under the Fifth, Eighth, and Fourteenth Amendments.61 As will be explored below, however, the legal standard for noncitizen detainees has been applied inconsistently, resulting in a patchwork of protections that is difficult to navigate. But before proceeding to such cases, it helps to first discuss DeShaney v. Winnebago County Department of Social Services,62 in which the Court established the broader framework for when, and as to whom, the government owes an affirmative duty to protect and provide care under the Due Process Clause.
B. Theories of Substantive Due Process Violations
DeShaney was a tragic case involving a young child who had been repeatedly beaten by his father.63 Social workers and local officers were allegedly aware of the possible abuse but failed to intervene.64 DeShaney and his mother brought suit under the Fourteenth Amendment, arguing that the officials’ “failure to act” had unconstitutionally deprived DeShaney of his liberty.65 The Court rejected this claim and declared that the Due Process Clause “confer[s] no [general] affirmative right to governmental aid.”66 The DeShaney Court thus championed the notion that the Constitution delineates what the government cannot do, rather than what it must do; individuals generally have no enforceable positive rights against the government.67
Importantly though, the Court carved out two exceptions to the rule of no duty. First, under the “special relationship” doctrine,68 it held that “when the State takes a person into its custody and holds him there against his will,”69 this triggers a special custodial relationship giving rise to “a corresponding duty to assume some responsibility for his safety and general well-being.”70 Second, under what has become known as the “state-created danger” doctrine, courts have found the government liable for affirmatively placing individuals in danger or positions of vulnerability that they would otherwise not have faced.71 In doing so, they point to language in DeShaney finding significant that the government neither “played [a] part in [the] creation” of the dangers that DeShaney faced, “nor did . . . anything to render him any more vulnerable.”72 While the elements of a state-created danger claim vary across circuits,73 a state-created danger suit commonly requires government action as opposed to mere failure to act74 and typically involves a higher level of culpability than deliberate indifference.75 For instance, the doctrine has been applied to find police officers liable for abandoning a passenger in a crime-prone area while arresting a motorist,76 and for kicking out an intoxicated bar patron and preventing him from getting into his car on an extremely cold night.77 With this background in mind, the following sections examine how DeShaney’s two exceptions have developed in the context of constitutional challenges by noncitizens.
1. Special Relationship Doctrine. — The special relationship doctrine imposes a duty on the government to provide “basic human needs” including “food, clothing, shelter, medical care, and reasonable safety” for persons held in its custody.78 This duty provides the basis for challenges by incarcerated and institutionalized individuals including immigrant detainees, who claim that confinement under the circumstances amounts to an unconstitutional “punishment[]” in violation of the Eighth Amendment and the Due Process Clauses.79
For prisoners, the controlling test is whether the government exhibited “deliberate indifference” to a basic human need.80 This includes both an objective and a subjective component: the government must have knowingly disregarded an objectively substantial risk to the prisoner’s health or safety.81 For pretrial detainees, the standard is less clear.82 While the Court has suggested that detainees awaiting trial without a conviction are entitled to “at least as great” protection as convicted prisoners are,83 it has done so without specifying whether this standard requires equal or greater protection.84 Bell v. Wolfish85 clarified that, in any case, pretrial detainees may not be held in “punitive” conditions, which exist if they are (1) expressly intended to punish; (2) not rationally related to a legitimate government objective; or (3) excessive to that objective.86 But lower courts have applied this test in different ways, with some “assimilat[ing] pretrial detainees’ claims to those by convicted prisoners, applying the Eighth Amendment standards to both,”87 and others suggesting that Bell’s reasonable-relationship test is purely objective.88
The case law for immigrant detainees has evolved largely parallel to that of pretrial detainees,89 but with some critical deviations and added layers of complexity. Here too, the case law remains in flux,90 and the fact-specific Bell test leads to varying outcomes.91 In addition, though, the continued perplexity over whether the plenary power doctrine or aliens’ rights tradition should govern amplifies uncertainties.92 Some courts have concluded that the government’s plenary discretion over the admission and exclusion of noncitizens should not affect noncitizens’ protection from inhumane treatment while detained.93 These opinions thus reaffirm the aliens’ rights tradition and reinforce the notion that substantive due process claims based on the government’s failure to protect fall outside the domain of immigration law.94 In contrast, others have invoked plenary power reasoning to hold that detained noncitizens who have not yet been admitted into the country possess only a limited right to be free from “gross physical abuse” or “malicious infliction of cruel treatment.”95 In effect, these decisions markedly deviate from the generally applicable standard for pretrial detainees and establish a uniquely stringent standard for a significant number of noncitizens.96
2. State-Created Danger Doctrine. — Claims by noncitizens under the state-created danger theory have similarly been shaped by the enduring influence of the plenary power doctrine. A particularly clear illustration of this impact is the Third Circuit’s decision in Kamara v. Attorney General of the United States,97 where a noncitizen challenged the government’s deportation order by contending that removal to his home country would affirmatively subject him to the likelihood of torture.98 Rejecting this argument, the court explained that granting such a claim “would impermissibly tread upon the Congress’ virtually exclusive domain over immigration.”99 It added that, as a matter of law, “the state-created danger exception has no place in our immigration jurisprudence.”100 Several courts have followed suit, citing Kamara for its categorical approach to foreclose the state-created danger exception as a theory of due process violation.101
Critically, others have gone further and extended Kamara to quite distinguishable facts. In particular, similar reasoning has been invoked to strike down claims by so-called “alien informants” who assist U.S. law enforcement and face a risk of retribution in their home country as a result of such activity.102 In one such case, a noncitizen argued that his cooperation with the U.S. government’s drug investigation implicating members of the Nigerian military created a risk of torture if he were to be deported.103 The district court allowed his claim to proceed, stressing that the plenary power doctrine was inapplicable, since at issue was not a “right to remain in the United States, but the right to live and . . . be free from state sanctioned torture, the danger of which . . . the executive created.”104 The court thus treated the availability of the state-created danger doctrine as a separate and distinct inquiry from whether the remedy sought implicated the government’s control over immigration.105 On appeal, however, the First Circuit reversed, echoing Kamara’s language that entertaining such a claim would be “an impermissible effort to shift to the judiciary the power to expel or retain aliens.”106 From this determination, it reached a sweeping conclusion that, regardless of whether a citizen might have a substantive due process right not to be exposed to state-created danger, a noncitizen facing removal has no such right.107
III. Toward an Affirmative Duty to Protect
A. The Recent Litigation
While the COVID-19 pandemic has devastated many communities, incarcerated and institutionalized individuals have felt some of its worst effects.108 Immigration detention facilities run by ICE were responsible for over 245,000 coronavirus cases between May and August 2020 alone, and detainees reported an infection rate thirteen times higher than that of the general population.109 This urgent reality has led to more than 100 lawsuits by immigrant detainees across the country challenging their conditions of confinement.110 Broadly, the suits argue that the detention facilities fail to comply with public health guidance by the Centers for Disease Control and Prevention111 (CDC) and ICE’s Pandemic Response Requirements (PRR).112
The litigation is ongoing and varied in form; however, the typical litigant moves for a temporary restraining order (TRO) seeking injunctive and declaratory relief in the form of temporary release and/or implementation of measures to improve the conditions of confinement.113 Under the standard for granting a TRO, the immigrant-detainee plaintiff is required to show (1) likelihood of success on the merits; (2) likelihood of irreparable harm in the absence of relief; (3) favorable balance of equities; and (4) furtherance of the public interest.114 Procedurally, the motions are filed under 28 U.S.C. § 2241, which allows federal judges to grant a writ of habeas corpus if the petitioner is held “in custody in violation of the Constitution.”115 While many are filed as separate habeas petitions, there have been a number of class actions seeking relief on a wider scale and providing important context for the litigation at large.116 For instance, the district court in Fraihat v. ICE117 certified a nationwide class including “[a]ll people who are detained in ICE custody who have one of the [CDC-recognized] Risk Factors placing them at heightened risk” of contracting COVID-19.118 Similarly, in Flores v. Barr,119 the district court overseeing the longstanding Flores Settlement Agreement ordered the release of all minors who had been detained at ICE-managed family residential centers for over twenty days.120
Unlike Flores, which involved whether the government breached its contractual obligations under a settlement agreement, many of the lawsuits address constitutional challenges under the Due Process Clause. The claims center around two distinct but related theories of substan-tive due process that derive from the principle established in DeShaney121 Jones v. Wolf, 467 F. Supp. 3d 74, 82 (W.D.N.Y. 2020) (noting that “[t]he petitioners’ claim [was] best understood as an amalgam of two theories of substantive Due Process violations: unconstitutional conditions of confinement and deliberate indifference to serious medical needs”); see also Habibi v. Barr, 445 F. Supp. 3d 990, 996 (S.D. Cal. 2020); Coreas v. Bounds, 451 F. Supp. 3d 407, 421 (D. Md. 2020); Pimentel-Estrada v. Barr, 458 F. Supp. 3d 1226, 1243 (W.D. Wash.), amended by 464 F. Supp. 3d 1225 (W.D. Wash. 2020). — namely, that the government must care for those who are unable to care for themselves “by reason of the deprivation of [their] liberty.”122 Specifically, plaintiffs have alleged that ICE’s inadequate response to the pandemic renders continued detention (1) an unconstitutional punishment123 and (2) a violation of the government’s affirmative duty to provide detainees with reasonable protection.124
To assess the likelihood of success on the merits of either claim, courts ask whether the condition or deprivation in question is punitive under the Bell test.125 Given the difficulty of showing an express punitive intent and in light of precedents recognizing the government’s legitimate interest in immigration detention,126 the relevant inquiry often becomes whether the conditions are “excessive” in relation to that objective.127 Under this excessiveness inquiry, courts look to whether the government acted with “deliberate indifference to the challenged condition[]” or deprivation.128 And here the courts remain divided129: some apply an objective test and inquire whether the government placed the detainee at “substantial risk of suffering” without taking “reasonable” mitigatory measures130 while others additionally require a subjective mens rea showing that the government actually knew of such risk.131
In either case, the inquiry considers “the totality of circumstances,” which inevitably invites different conclusions based on various permutations of factors such as the petitioner’s health or the specific precautions taken by each detention facility.132 For instance, a young and healthy petitioner in a private cell may be denied relief, whereas an elderly petitioner with underlying medical conditions in a shared cell may prevail.133 Likewise, what constitutes a “reasonable” measure of protection depends on the specific factual context.134
As to the remaining factors under the TRO standard, some decisions have found that the likelihood of irreparable harm is “speculative” or “too attenuated” when petitioners lack preexisting medical conditions, or when there are no confirmed cases of COVID-19 at the particular facility.135 The analysis of the balance of equities and the public interest similarly hinges on a weighing of factors including the potential public health impact of releasing the detainee136 and the strength of the government’s interest in keeping the individual detained, which in turn varies depending on whether the detention was mandatory or discretionary under the statutory immigration scheme.137
As such, the lawsuits involve fact-intensive analyses and have produced considerably different outcomes — ranging from orders granting immediate release,138 to orders denying relief upon findings that the particular condition was not “excessive,”139 to orders dismissing the petition based on a threshold issue of jurisdiction.140 Yet others have admonished “blanket release from immigration detention” as an inappropriately broad remedy141 and granted the motion only in part, mandating narrower remedies such as the cure of deficient conditions or compelled compliance with specific preventive measures.142
B. Limits and Implications
Before analyzing the wider implications of the recent lawsuits, it helps to first acknowledge a number of limitations. Perhaps most obviously, the fact-specific analyses and inconsistencies among courts may lessen the precedential impact of any particular outcome. One might also argue that the cases, taken together, have limited future application, given that COVID-19 itself presents a unique challenge with unparalleled urgency, requiring extraordinary measures.143 Yet another limitation could be the difficulty of extending cases that grant predeprivation equitable relief to postdeprivation damages claims.144
Despite these caveats, analyzing lower court decisions and identifying common themes is both important and instructive, especially in the absence of definitive Supreme Court guidance.145 This section highlights one such crosscutting theme: the explicit recognition by courts that — even if the facts of the particular case require denial of relief — the government nonetheless owes an affirmative duty to protect and provide adequate care for noncitizen detainees.146 Given the rarity of cases that directly recognize and address the scope of such a duty,147 the new slew of decisions that foreground an affirmative duty to protect noncitizens is significant in itself. If anything, this rhetoric marks a shift away from the narrative that the government owes a bare minimum to noncitizens — a notion still prevalent in legal and political discourse, partly due to the longstanding doctrine that the admission of noncitizens is a “matter of pure permission, of simple tolerance, and creates no obligation,”148 and the related notion that even after they set foot on American soil, the default expectation is for noncitizens to remain self-sufficient.149
More concretely, though, the recent addition to case law provides much-needed clarity for litigants with regard to the availability of substantive due process claims under DeShaney’s two exceptions. This development has practical significance for immigration detention litigation more broadly. For instance, cases that expressly recognize noncitizen detainees’ constitutional right to safety and medical care help counter the qualified immunity defense, which shields government officers from suit if their conduct does not violate a “clearly established” right and often poses a substantial hurdle for noncitizens seeking monetary damages under 42 U.S.C. § 1983.150
Furthermore, while the bulk of the pandemic-related lawsuits rely on DeShaney’s special relationship doctrine,151 recognizing a broader affirmative duty to protect also reinforces claims under the state-created danger doctrine, insofar as the two are derived from the same underlying principle. This, in effect, weakens Kamara-like cases that categorically foreclose the state-created danger doctrine for noncitizen detainees facing deportation.152 That is, if DeShaney’s first exception can be invoked to grant release (albeit temporary) from custody, it is unclear why the second exception “has no place” simply because the remedy sought is relief from removal.153 Establishing the validity of the state-created danger doctrine has potentially wide-ranging implications, as demonstrated by the groundbreaking ruling in J.P. v. Sessions,154 where a district court invoked the doctrine to mandate government-provided mental health services for immigrant families who were forcibly separated at the border.155
Another noteworthy aspect of the pandemic litigation is that several of the cases directly addressed and expressly rejected the argument that “noncitizen immigration detainees are entitled to lesser due process protections than citizens.”156 Critically, others went further and concluded that for purposes of substantive due process analysis, excludable noncitizens and removable noncitizens are treated alike.157 As one court explained: “[All] petitioners claim that the government is forcing them to live in conditions that fall below acceptable societal standards of decency. By holding [excludable petitioners] in detention, the respondents have assumed a burden they cannot ignore — [their] status as . . . excludable alien[s] notwithstanding.”158 Echoing the language in DeShaney, these opinions have offered a straightforward explanation for placing all noncitizens on an equal footing with citizens: “[T]he power to incarcerate implies the duty to protect.”159 That is, the government’s duty to protect arises not from the detainee’s individual legal status, “but from the limitation which [the government] has imposed on [the detainee’s] freedom to act on his own behalf.”160
These decisions thus directly challenge precedents that have held excludable noncitizens to the uniquely high standard of “gross physical abuse” or “malicious infliction of cruel treatment.”161 A broader implication, however, is that by extending DeShaney’s rationale to the context of immigration detention, they implicitly reject the plenary power doctrine as inapplicable to substantive due process claims alleging the government’s failure to protect or provide care. That is, the opinions subtly but clearly shift away from cases that withhold due process protections from noncitizens based on the subject matter in controversy, or otherwise tailor protections based on noncitizens’ level of “voluntary connection[s]” to the community.162 Instead, by adopting DeShaney’s rationale in full, the decisions identify the locus of protections for noncitizens as the government’s involuntary control over them and its causal role in creating or exacerbating the danger in question.
Conclusion
This Note has examined an issue that is increasingly important yet continues to suffer from an unfortunate lack of clarity: the extent of the government’s duty to protect noncitizens in immigration detention. Parts I and II discussed the broader constitutional framework and examined how the case law in this area often tolerates ambiguity and apparent inconsistencies. Part III considered how recent challenges to conditions arising from the COVID-19 pandemic may suggest a shift in the legal landscape. As scholars have previously noted, constitutional principles in immigration law are shaped by unprecedented events that test the limits of immigration jurisprudence and compel courts to seek “new answers to . . . fundamental questions.”163 This Note suggests that the COVID-19 pandemic is one such event. The decisions that recognize immigrant-detainee claims under DeShaney collectively stand for the proposition that the government, by virtue of its own actions, assumes a positive constitutional duty to protect and care for those individuals that it detains — irrespective of their citizenship status.