
With a conservative majority, the court ruled that the government did not present a legal basis to justify such mobilization, authorized by law in exceptional circumstances. This represents a rare departure from recent instances in which the conservative majority came out overwhelmingly in favor of Trump in preliminary tests of presidential power.
Three conservative justices – Clarence Thomas, Samuel Alito Jr. and Neil Gorsuch – recorded their dissenting opinions.
The Republican president also mobilized troops in cities like Washington, Los Angeles and Chicago, cities governed by Democrats, with the argument of fighting crime and strengthening his campaign against undocumented immigrants.
Critics argue that federal law prohibits the use of military troops to enforce the law domestically, while supporters say troop assistance to federal agents and local police is legal and necessary.
Much of the dispute stems from the hybrid nature of the National Guard, which is both a component of the nation’s armed forces and a resource available to state governors to respond to civilian needs.