Alito, J., dissenting
The Court points to what it sees as a “represent[ation]” by the Solicitor General that the Final Memorandum does not affect “continued detention of noncitizens already in federal custody.” Ante, at 12, n. 5. But as Justice Barrett notes, the Government argued that when it chooses not to remove someone under the Final Memorandum’s guidance, its mandatory detention obligation ends—meaning it is asserting discretion over continued detention. Ante, at 3 (opinion concurring in judgment).
In any event, arrest policy cannot be divided from detention policy in this case. When a person is arrested, he or she is detained for at least some period of time, and under the detainer system involved here, “arrest” often simply means transferring an immigrant from state custody to federal custody. As best I can tell, the majority’s distinction between arrest and detention is made solely to avoid the obvious inference that our decision last Term in Biden v. Texas should have dismissed the case for lack of standing, without analyzing “the Government’s detention obligations.” 597 U. S., at ___ (slip op., at 14).
In sum, with the exception of cases in the first (very small) category (civil cases involving selective-prosecution claims), the majority does not identify any category of cases that it would definitely except from its general rule. In addition, category two conflates the question of constitutional standing with the question whether the plaintiff has a cause of action; category three is hopelessly vague; category four is incomprehensible; and category five actually encompasses the case before us.
IV
The Court declares that its decision upholds “[o]ur constitutional system of separation of powers,” ante, at 9, but as I said at the outset, the decision actually damages that system by improperly inflating the power of the Executive and cutting back the power of Congress and the authority of the
