Ms. L. v. U.S Immigration & Customs Enforcement, 310 F. Supp. 3d 1133

Plaintiffs (parents) challenge a government practice of separating parents from their minor children at the border and failing to reunify them absent a determination the parent is unfit or dangerous. Plaintiffs brought a classwide action seeking a preliminary injunction.
The sole claim at issue is a substantive due process claim: family integrity rights under the Fifth Amendment, measured by the "shocks the conscience" standard.
The record shows separations occurred both before and after the administration's "zero tolerance" policy and affected parents who lawfully presented at ports of entry seeking asylum.
The government lacked effective procedures to track separated children, enable parent–child communication, or proactively reunify parents and children; reunification was often delayed for months and typically required litigation.
The court found that separations caused severe emotional and developmental harms to children and acute distress to parents, and that constitutional injury (and irreparable harm) was likely.
The court granted a classwide preliminary injunction ordering (inter alia) that parents not be detained apart from their minor children absent a fitness/danger finding or a knowing voluntary declination to reunify; timeframes and communication/tracking steps for reunification were mandated.

Issue	Plaintiff's Argument	Defendant's Argument	Held
1. Likelihood of success on substantive due process claim	Separation of parents and children without a fitness/danger determination "shocks the conscience" and violates family integrity	Border enforcement and detention authority justify separations when necessary to enforce criminal/immigration laws	Court: Plaintiffs likely to succeed; family integrity applies at the border and practice as implemented is conscience-shocking given lack of individualized findings and procedures
2. Irreparable harm	Separation of parent and child is an irreparable constitutional injury causing severe, long-term harm to children and parents	Government enforcement interests outweigh claimed harms; separations necessary in some enforcement contexts	Court: Irreparable harm established; constitutional deprivation and serious documented harms support injunction
3. Balance of equities	Ending an unlawful practice imposes minimal burden on government and prevents severe harm to families	Injunction could impede enforcement of criminal and immigration laws	Court: Equities tip to plaintiffs; injunction does not bar enforcement but requires it to be conducted consistent with constitutional rights
4. Public interest	Public interest favors protecting constitutional family rights and children's welfare	Public interest in effective law enforcement	Court: Public interest supports injunction; both enforcement and family integrity can be accommodated

County of Sacramento v. Lewis, 523 U.S. 833 (1998) (describing "shocks the conscience" standard for substantive due process)
Winter v. Natural Resources Defense Council, 555 U.S. 7 (2008) (preliminary injunction standard requires likelihood of success and irreparable harm)
Univ. of Texas v. Camenisch, 451 U.S. 390 (1981) (plaintiff need not prove entire case at preliminary injunction stage)
Santosky v. Kramer, 455 U.S. 745 (1982) (parental rights are more precious than property interests)
Troxel v. Granville, 530 U.S. 57 (2000) (parental rights as fundamental liberty interest)
Garcia v. Google, Inc., 786 F.3d 733 (9th Cir. 2015) (noting likelihood of success is most important Winter factor)
Leiva-Perez v. Holder, 640 F.3d 962 (9th Cir. 2011) (family separation constituting irreparable harm)
Rodriguez v. Robbins, 715 F.3d 1127 (9th Cir. 2013) (ending unlawful practice imposes no harm on government; equitable considerations)
Arizona Dream Act Coalition v. Brewer, 757 F.3d 1053 (9th Cir. 2014) (constitutional violation favors injunction; public interest consideration)
Brokaw v. Mercer County, 235 F.3d 1000 (7th Cir. 2000) (state has no interest in removing children absent reasonable suspicion of abuse or imminent danger)