March 05, 2020

Nielson v. Preap


What is the Scope of the Government’s Power to Detain Someone After the Serving of a Criminal Sentence?


Immigration law generally gives the Department of Homeland Security discretion to determine whether to detain certain aliens who have been released from prison recently. The justification for such a policy is the belief that some aliens pose either a flight or danger risk to others. The traditional default section provides that the government has discretion on whether to institute removal proceedings against an alien who has committed certain crimes. Under this system, the alien is entitled to a bond hearing. However, another provision of the code provides for mandatory detention of certain aliens who are deemed dangerous. This provision provides that the government “shall” detain these individuals after the completion of their criminal sentences. This case deals with the situation where aliens serve criminal sentences and qualify for mandatory deportation under the federal code. However, for unknown reasons, some individuals serve their criminal sentences and are then allowed to go back to their families and communities. Only then, years later, immigration officials show up and detain them for deportation.

Nielson v. Preap
Docket No. 16-1363
Argument Date: October 10, 2018
From: The Ninth Circuit
by David L. Hudson Jr.
Belmont Law School, Nashville, TN


Does a criminal alien become exempt from mandatory detention under 8 U.S.C. § 1226(c) if, after the alien is released from criminal custody, the Department of Homeland Security (DHS) does not take him into immigration custody immediately? 


Respondents are aliens who committed crimes that subject them to removal proceedings under immigration law. They served their criminal sentences and, upon their release, returned to their families and resumed their lives. However, years later, immigration authorities took them into custody and detained them without bond hearings. 

Respondents contend since they were not detained when they were released from their criminal sentences, they were not subject to mandatory removal under immigration law. Take the example of respondent Mony Preap. He has been a lawful permanent resident of the United States since 1981, after immigrating from Cambodia as an infant. He has two misdemeanor convictions for marijuana possession. 

Released after serving time for those convictions, he returned to his family life. However, after serving a short sentence for battery, authorities transferred him for immigration detention and he was held without a bond hearing. (After this litigation was filed, Preap was granted cancellation of removal and released from immigration custody. ) 

In a separate case that has been consolidated with the Preap case—the Khoury case—lead plaintiff Bassam Yusuf Khoury is a lawful permanent resident who has a 2011 conviction for attempted manufacture or delivery of a controlled substance. His conviction triggered a mandatory detention under Section 1226(c). He was released in June 2011, and DHS arrested him in April 2013. 

Federal district courts in California (in the Preap case) and in Washington (in the Khoury case) both agreed that the mandatory detention statute only applied to those aliens who were detained right after the completion of their criminal sentences—not to those who were detained years after the completion of their criminal sentences. The Ninth U.S. Circuit Court of Appeals agreed. 

The government petitioned for a writ of certiorari, which the Court granted. 


The Secretary of Homeland Security (Secretary) may issue a warrant for the arrest and detention of an alien, “pending a decision on whether the alien is to be removed from the United States.” 8 U.S.C. 1226(a). Under this process, the Department of Homeland Security has the discretion to detain a recently released inmate subject to an individualized bond hearing by an immigration judge. 

However, another provision of the statutory scheme, Section 1226(c) is titled mandatory detention. That section requires the Secretary to detain certain criminal and terrorist aliens during their removal proceedings, without the potential for release on bond. Paragraph (1) of Section 1226(c) mandates that the Secretary “shall” take custody of certain aliens, and Paragraph (2) of Section 1226(c) provides that the Secretary “may release an alien described in paragraph (1)” of that section “only if ” the narrow witness-protection exception applies. 8 U.S.C. § 1226(c)(2).

The two sections provide: 

(c) Detention of criminal aliens 

(1) Custody 

The Attorney General shall take into custody any alien who— 

(A) is inadmissible by reason of having committed any offense covered in section 1182(a)(2) of this title,

(B) is deportable by reason of having committed any offense covered in section 1227(a)(2)(A)(ii), (A)(iii), (B), (C), or (D) of this title,

(C) is deportable under section 1227(a)(2)(A)(i) of this title on the basis of an offense for which the alien has been sentenced to a term of imprisonment of at least 1 year, or

(D) is inadmissible under section 1182(a)(3)(B) of this title or deportable under section 1227(a)(4) (B) of this title, 

when the alien is released, without regard to whether the alien is released on parole, supervised release, or probation, and without regard to whether the alien may be arrested or imprisoned again for the same offense.

(2) Release 

The Attorney General may release an alien described in paragraph (1) only if the Attorney General decides pursuant to section 3521 of title 18 that release of the alien from custody is necessary to provide protection to a witness, a potential witness, a person cooperating with an investigation into major criminal activity, or an immediate family member or close associate of a witness, potential witness, or person cooperating with such an investigation, and the alien satisfies the Attorney General that the alien will not pose a danger to the safety of other persons or of property and is likely to appear for any scheduled proceeding. A decision relating to such release shall take place in accordance with a procedure that considers the severity of the offense committed by the alien.

The government (petitioner) contends that a detained alien is subject to mandatory detention under Section 1226(c), regardless of whether DHS arrested him immediately upon his release from criminal custody. Thus, under petitioner’s interpretation, all criminal aliens listed in the statute are subject to mandatory detention regardless of when DHS detains them. 

Petitioner notes that Congress passed the mandatory detention provision because it was “justifiably concerned that deportable criminal aliens who are not detained continue to engage in crime and fail to appear for their removal hearings in large numbers.” Demore v. Kim, 538 U.S. 510 (2003).

However, respondents counter that the purpose of the mandatory detention statute was to place certain aliens, recently released from prison, into detention so removal proceedings could be instituted. In other words, Congress intended there to be continuous custody of these dangerous aliens. Respondents argue that “[t]he government retains the authority to detain a noncitizen after she is released, but subject to the default detention framework in Section 1226(a).”

To respondents, it makes little sense to read the statute to give the government unfettered discretion to reach into communities and pluck aliens from their familial lives—even years after release from prison—and subject them to detention. Respondents write that the government’s “interpretation thus transforms a mandate to take custody at a particular point in time into a discretionary invitation to take custody at whatever time the Secretary decides after release from criminal custody.”

Constitutional and Immigration Law Professors, in their amicus brief in support of respondents, contend that due process principles support the respondents’ interpretation of the statutes. They point out that individuals who have left criminal custody and re-engaged in familial and community life are far less likely to be a flight risk than those who recently emerge from a criminal sentence. According to the professors, “a neutral decisionmaker must determine that physical confinement is necessary to prevent flight or danger.”

The parties differ over whether there should be deference given to the Board of Immigration Appeals’ (BIA) interpretation of the statute. The BIA interpreted the mandatory detention statute similar to the petitioner’s interpretation. The petitioner asserts that deference should be given to the BIA’s interpretation: “At a minimum, the BIA reasonably interpreted Section 1226(c), and that decision warrants deference under Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 843–844 (1984).” 

Respondents disagree, finding the BIA’s interpretation to be an unreasonable reading of the statute. They also argue that Chevron deference is not appropriate when the executive branch is dealing with habeas relief: “Deferring to the Executive’s interpretation of its own detention authority would undermine this core function of habeas review.” 


The case is significant because it impacts both the petitioner’s security concerns and the personal liberty concerns of respondents. Petitioners assert that the government must have the ability to detain and deport aliens who commit serious crimes. Otherwise, the immigration system is not serving its function. 

On the other hand, respondents emphasize the dramatic loss of liberty and unsettling of familial relations caused when the government comes to individuals’ homes years after they have completed their criminal sentences and breaks up their lives with the threat of long-term confinement and deportation. The Advancement Project, in its amicus brief, tells the stories of immigrants who have developed significant familial and community ties before suddenly being subjected to detention by immigration agents, even though they long ago served their criminal sentence. “Mandatory detention is offensive to liberty everywhere, but particularly so when applied to immigrants who have already returned to their communities,” the group argues.

An interesting argument advanced by the Immigration Reform Law Institute concerns the lack of cooperation that federal immigration officials receive from state and local officials. The group points out that in 2018, there are 564 different jurisdictions that “in some way curb or prohibit cooperation between state and local officials and DHS.”

The case is also significant because the Court could determine whether Chevron deference applies in this type of immigration setting, detention, that is similar to the criminal law setting. 

David L. Hudson Jr. is a visiting associate professor of legal practice at Belmont Law School in Nashville, Tennessee. He is also the author, coauthor, or coeditor of more than 40 books, including a coeditor of The Encyclopedia of the Fourth Amendment (2013). He can be reached at

PREVIEW of United States Supreme Court Cases 46, no. 1 (October 1, 2018): 34–36. © 2018 American Bar Association 


  • For Petitioner Kirstjen M. Nielson (Noel J. Francisco, Solicitor General, 202.514.2217) 

  • For Respondents Mony Preap, et al. (Michael K.T. Tan, 212.549.2500)


In Support of Petitioner Kirstjen M. Nielson

  • Criminal Justice Legal Foundation (Kent Scheidegger, 916.446.0345) 

  • Immigration Reform Law Institute (Christopher J. Hajec, 202.232.5590) 

  • U.S. Reps. Andy Biggs et al. (Richard Samp, 202.588.0302)

In Support of Respondents Mony Preap, et al.

  • Administrative and Immigration Law Professors (Anton Metlitsky, 212.326.2000)

  • Advancement Project et al. (Alina Das, 212.998.6430)

  • Constitutional and Immigration Law Professors (Mark C. Fleming, 617.526.6000) 

  • Former INS and General Counsels (Matthew E. Price, 202.639.6873)

  • Members of Congress (Jayashri Srikantiah, 650.724.2442)

  • National Immigrant Justice Center (Elaine J. Goldenberg, 202.220.1100)