Is This Supreme Court Case About Birthright Citizenship? Yes and No.

When the justices hear oral arguments on Thursday in a challenge related to President Trump’s ban on birthright citizenship, they will face an issue that sounds like a blockbuster: Can the president upend birthright citizenship, long held up as a bedrock of the United States?

But the legal question before the justices is actually much narrower.

For now, the justices have been asked to look only at the legality of the nationwide pauses, which are called national injunctions, that are blocking President Trump’s executive order that would end birthright citizenship for the children of undocumented immigrants and some temporary foreign residents.

A case focused on the policy itself — whether the 14th Amendment of the Constitution requires birthright citizenship for children born on American soil — could come later, but lawsuits challenging the policy are still at early stages in federal trial courts.

The constitutionality of Mr. Trump’s executive order may well come up, along with the practicality of allowing patchwork citizenship rules in different states should the justices decide that national injunctions are not allowed.

But the bulk of the argument Thursday from three lawyers — the U.S. solicitor general, D. John Sauer; the New Jersey solicitor general; and a lawyer arguing on behalf of immigrant advocacy groups and individuals — is expected to concern the legality of injunctions, and whether a single federal judge can issue an order temporarily freezing a policy for the entire country.

Nationwide injunctions have been a contentious subject for years. The tool has been used under both Democratic and Republican administrations.

Although the Supreme Court has yet to issue a ruling that squarely addresses nationwide injunctions, some of the conservative justices have expressed skepticism that federal courts can block policies for the entire country.

Justice Neil M. Gorsuch, in an opinion in 2020, criticized injunctions of “‘nationwide,’ ‘universal’ or ‘cosmic’ scope,” writing that such “patently unworkable” rulings were “sowing chaos.”

In a dissent in an emergency application in March, Justice Samuel A. Alito Jr. criticized “the unchecked power” of a district judge who had ordered the State Department to release roughly $2 billion to contractors for the U.S. Agency for International Development. Justices Gorsuch, Clarence Thomas and Brett M. Kavanaugh joined him.

In a friend-of-the-court brief, Mila Sohoni, a law professor at Stanford who has published law review articles arguing that such injunctions are constitutional, argued that nationwide injunctions were the best way to keep the status quo in place while lower court challenges proceed, preventing a patchwork of policies.

Opponents say these injunctions give far too much power to a single judge and improperly thwart national policies. The West Virginia attorney general’s office, in a friend-of-the-court brief, argued that “broad injunctions like those seen here invite all sorts of mischief” and are an improper overreach of federal courts that comes “at the expense of state power.”