This Thursday, the U.S. Supreme Court will hear arguments on a high-stakes case challenging President Trump’s executive order ending birthright citizenship.

Signed on Inauguration Day of his second term, the order restricts citizenship to children with at least one U.S. citizen or permanent resident parent—directly challenging the 14th Amendment.

Lower courts have blocked the order, calling it likely unconstitutional. If upheld, it could deny birthright citizenship to an estimated 255,000 babies born in the U.S. each year.

This marks the Court’s first review of a second-term Trump policy and could redefine the scope of nationwide injunctions. A final ruling is expected by July, with major implications for immigration and constitutional law.