In early 2019, President Trump’s Department of Homeland Security (DHS) implemented a policy known as the Migrant Protection Protocols (MPP), which requires certain noncitizens arriving at the southwest border to remain in Mexico during the pendency of their immigration proceedings. In June 2021, President Biden’s Secretary of Homeland Security issued a memorandum terminating MPP based on several considerations, including the extent of resources needed to implement the program, the availability of other more effective and humane border-management approaches, and the impact of MPP on the country’s relationship with Mexico.

The states of Texas and Missouri filed suit against the Biden administration in federal court, arguing that the termination of MPP was unlawful. The district court ruled in favor of the states, and the United States Court of Appeals for the Fifth Circuit affirmed. Among other things, the Fifth Circuit held that 8 U.S.C. § 1225 imposes a statutory obligation to return to a contiguous territory—like Mexico—all arriving noncitizens who are not clearly admissible and whom it lacks the capacity to detain, and that DHS needed to reinstate MPP to comply with this obligation. The Biden administration asked the Supreme Court to hear the case, and the Court agreed to do so.

CAC filed an amici curiae brief on behalf of a bipartisan group of former Department of Homeland Security and Immigration and Naturalization Service officials, arguing that the Fifth Circuit’s interpretation of 8 U.S.C. § 1225 is contrary to the plain meaning of the statute and the manner in which DHS and INS officials, in both Republican and Democratic administrations, have managed the border for decades. Our brief makes three main points.

First, our brief demonstrates why the Fifth Circuit erred in construing 8 U.S.C. § 1225 as containing an unyielding “detention mandate.” Such an interpretation ignores the larger statutory scheme of the INA which includes discretionary exceptions to detention. Indeed, 8 U.S.C. § 1225(b)(2)(A) could not be a “detention mandate”—and has never been treated as one—because Congress has never appropriated sufficient funds for DHS to detain all arriving noncitizens who are not clearly admissible.

Our brief further argues that even if § 1225(b)(2)(A) could validly be construed as a detention mandate, the Fifth Circuit was still wrong to conclude that a discretionary policy like MPP is mandatory. This construction ignores the plain text of the statutory provision authorizing MPP, 8 U.S.C. § 1225(b)(2)(C), which states that DHS “may return” certain noncitizens to a contiguous territory pending immigration proceedings.

Second, our brief explains that the Fifth Circuit should have recognized parole as a viable discretionary alternative to detention or contiguous territory return. The parole authority in 8 U.S.C. § 1182(d)(5)(A) permits applicants for admission to be temporarily released on parole on a “case-by-case” basis. While the Fifth Circuit acknowledged the parole authority, it erroneously reasoned that termination of MPP would result in mass adjudication of parole in violation of the case-by-case requirement of § 1182(d)(5)(A). However, as our brief explains, this interpretation not only defies the statutory text by erroneously inferring that “case-by-case” implies “a small number,” it also runs counter to the longstanding use of the parole authority to manage large numbers of noncitizens at the southwest border in the face of insufficient detention capacity.

Third, our brief explains that by converting a discretionary option into a mandate, the court below failed to respect the significant enforcement discretion that Congress has long conferred on the executive branch in the realm of immigration policy. That discretion necessarily includes making detention determinations, as every administration over the past twenty-five years has recognized. Contiguous territory return illustrates why executive discretion in this realm is so important: it necessarily requires the United States to send noncitizens into the territory of a foreign sovereign and thus has the potential to have significant implications for the nation’s foreign policy. Indeed, even the administration that first implemented MPP recognized this principle, formally implementing MPP only after negotiating the terms of the program with Mexico and obtaining that nation’s affirmative consent.

In sum, the decision of the court below defied statutory text, structure, and history, ignored the parole practices of every administration in recent history, and disregarded the principles of prosecutorial discretion embedded in our nation’s immigration laws.