The U.S. Supreme Court on Tuesday rejected President Donald Trump's attempt to end birthright citizenship in the United States via executive order. The 6-3 decision reaffirms more than a century of legal precedent and national tradition, stating that babies born on American soil are automatically U.S. citizens.

This ruling marks a significant blow to President Trump, who had actively lobbied the court to uphold his "Day 1" executive order. Trump himself attended the oral arguments in the case, becoming the first sitting president to do so.

In the majority opinion, Chief Justice John Roberts wrote that citizenship has always been the "right to have rights" and that the Framers of the Fourteenth Amendment extended this promise to "every free-born person in this land." He emphasized, "We keep that promise today."

The decision preserves the status quo, meaning hundreds of thousands of children born annually to non-citizen parents will continue to be granted citizenship automatically. Immigrant advocates and civil liberties groups had warned that the executive order would have created a "bureaucratic nightmare" and could have left some children stateless.

Justices Clarence Thomas, Neil Gorsuch, and Samuel Alito dissented. Thomas and Gorsuch argued that neither the Constitution nor federal law guarantees citizenship to individuals not domiciled in the United States. Thomas suggested that the domicile of a child's parents should be the primary indicator of citizenship, citing the nation's history and tradition.

President Trump had contended that children born to undocumented immigrants and temporary visitors, such as tourists and foreign students, should not qualify for citizenship under the terms of the 14th Amendment. This amendment, ratified after the Civil War, was originally intended to address the status of formerly enslaved people and their descendants.

The ACLU, which argued the case before the court, celebrated the decision. Legal Director Cecilia Wang stated that a president cannot alter the Constitution by executive decree and that the court's ruling "stands strong" in reaffirming birthright citizenship.

According to the Migration Policy Institute, an estimated 255,000 children born each year to non-citizen parents would have lost legal status under the executive order. Prior to the Supreme Court's ruling, every lower court that considered Trump's order had deemed it unlawful and issued injunctions to halt its implementation.