Each year, the United States deports over 100,000 noncitizens through “expedited removal,” a fast-tracked deportation process. In creating the system, Congress intentionally limited procedural protections for certain immigrants, allowing judges reviewing these removal orders to consider only three narrow questions: whether the immigrant is a noncitizen, has been ordered removed, or is a lawful permanent resident, refugee or asylum seeker.

Vijayakumar Thuraissigiam, a Sri Lankan national who sought asylum in the United States, challenged that limit, arguing that it was an unconstitutional barrier to habeas corpus, a right that allows a judge to review whether someone is legally detained.

On Thursday, the Supreme Court disagreed, issuing a sweeping ruling in Department of Homeland Security v. Thuraissigiam. As others have noted, its ruling has many important implications for immigrant rights. But the way the Supreme Court wrote its opinion could expand the decision’s implications beyond immigration, perhaps even affecting the constitutional legacy of what President George W. Bush called the “war on terror.”

The Supreme Court, the war on terror and Guantánamo

After terrorists attacked the United States on Sept. 11, 2001, the government began detaining people it had identified as hostile individuals at a naval base in Guantánamo Bay, Cuba. Guantánamo was chosen because it’s a legal gray zone, located on Cuban land leased to the U.S. government. Bush administration lawyers suggested that courts would not exercise habeas jurisdiction there.

Lawyers for the detainees went to court to contest whether their detention was legal. In 2004, the Supreme Court held that federal law provided the Guantánamo detainees access to habeas corpus review of their confinement. Congress backed the president and passed a statute that almost eliminated habeas jurisdiction over the Guantánamo detainees. The court reviewed that provision in a 2008 decision, Boumediene v. Bush, where a 5-to-4 majority led by Justice Anthony M. Kennedy rebuked the executive branch, emphasizing the importance of judicial authority in our government of separated powers.

Take note of that fact: The Supreme Court pushed back on presidential power — something it has rarely done. As political scientist Gordon Silverstein explains, the Boumediene decision “saw not simply an aggressive executive claiming independent power or pressing Congress to delegate power to the administration — it saw the elected branches employing creative devices … to usurp what the majority saw as the independent power of the judicial branch itself.”

Thuraissigiam decision lays three discrete land mines that could undermine this legacy

Justice Samuel A. Alito Jr.’s majority opinion in Thuraissigiam says very little about Boumediene, simply noting that the decision was “not about immigration at all.” But the omissions may undermine Boumediene’s authority.

First, Boumediene said that the Constitution guarantees an affirmative right to habeas, contained in what’s called the suspension clause. That clause has long been a constitutional curiosity because of its negative phrasing: It provides only that “[t]he Privilege of the Writ of Habeas Corpus shall not be suspended” except in certain cases. Many scholars have understood the ruling in Boumediene to have held that the suspension clause does guarantee a constitutional right to habeas review.

Despite this consensus, the majority in the Thuraissigiam opinion seems to suggest the matter is unsettled. In fact, the opinion includes a footnote describing the “controversy” over whether “the original meaning of the Suspension Clause … independently guarantees the availability of the writ or simply restricts the temporary withholding of its operation.” As its authority, the opinion refers only to a 2001 case about immigration, issued before Boumediene.

Second, Boumediene found that the Constitution guarantees habeas corpus rights even to detainees the Bush administration held as “enemy combatants.” That was true even though the detainees weren’t citizens. In fact, as legal scholar Gerald Neuman put it, Boumediene “confirmed and held that the Suspension Clause constitutionally guarantees habeas corpus to noncitizens” (emphasis original). The Thuraissigiam majority opinion, however, characterizes Boumediene as “forming ‘no certain conclusions’ ” on whether habeas rights extend to “alien[s] who lack … any allegiance to the country.”

Third, as scholars have noted, Boumediene emphasized the importance of an independent judiciary’s review of detention decisions made solely by the executive branch, insisting that the constitutional separation of powers requires this kind of oversight. Thuraissigiam has essentially thrown that out, at least in the context of asylum proceedings. Despite the life-or-death implications of asylum proceedings, these decisions are made almost exclusively within the executive branch. Shutting the door to Thuraissigiam’s habeas petition surely raises the kind of separation-of-powers concerns paramount to the justices in Boumediene. Yet the phrase “separation of powers” doesn’t even appear in the majority’s 36-page opinion.

Will the Supreme Court reconsider its ‘war on terror’ rulings?

In last week’s ruling, the court treated questions that Boumediene decided as undecided, and it ignored a mode of analysis that Boumediene emphasized. That suggests that five justices may be willing to reconsider the case.

Earlier this year, journalist and legal analyst Linda Greenhouse discussed the “war on Boumediene.” Two years ago, law professor Stephen Vladeck noted that a major difference between then-Judge Brett M. Kavanaugh and Kennedy was in how they ruled on the Guantánamo cases.

In Boumediene, the court resisted the political branches’ encroachment into its authority. In Thuraissigiam, the court backed away from that stance, leaving the constitutional rights of tens of thousands of immigrants to Congress and the president.

The Roberts court is known for “tee[ing] up major constitutional issues for dramatic reversal.” It could be doing so again.

Isaac Cui recently graduated from Pomona College, where he studied politics and physics. He is a 2020 Marshall Scholar and will be studying at the London School of Economics in the fall.