The United States Supreme Court today struck down President Donald Trump’s attempt to end birthright citizenship as it has been understood for more than a century. The Court invalidated an executive order that was a key part of President Trump’s agenda.

The ruling is a major setback for President Trump. During his election campaign, he had promised to end what he called “birthright tourism.” Since returning to office for his second term, his administration has focused heavily on tightening rules for both legal and illegal immigration.

The Supreme Court’s decision confirms the long-standing understanding that anyone born in the United States is a US citizen, even if the child’s parents are not.

Chief Justice John Roberts wrote the majority opinion, which was joined by both conservative and liberal justices. However, three conservative justices—Clarence Thomas, Samuel Alito, and Neil Gorsuch—dissented.

Chief Justice Roberts wrote, “Citizenship, then and now, was the right to have rights—to freely participate in our political community.” He further wrote for the Court, “The framers of the Fourteenth Amendment extended that promise to ‘every free-born person in this land.’ We keep that promise today.”