Eight justices—the exception being Ketanji Brown Jackson—seem keen to rein in universal injunctions. But a majority also appear committed to averting Mr Trump’s radical departure from the constitution’s promise of citizenship. The justices could thread that needle in three ways.

The Justices on the Supreme Court wrestled on Thursday with a high-stakes case involving birthright citizenship that’s poised to shape both the Trump Administration’s immigration policy and its attempts to expand presidential power.