WASHINGTON — The Supreme Court of the United States issued one of its most far-reaching immigration decisions in decades on Tuesday, voting 6-3 in Trump v. Barbara to uphold birthright citizenship under the Fourteenth Amendment and strike down President Donald Trump’s executive order seeking to restrict it — a ruling that Rep. Mary Miller (R-IL) called deeply disappointing and a failure to address what she characterized as one of the most serious vulnerabilities in the American immigration system.
Posting to X at 10:54 a.m. on June 30, 2026 — among the earliest congressional reactions of the day — Rep. Miller wrote:
“The Supreme Court made the disappointing decision to leave one of the greatest abuses of our immigration system untouched.
Congress has the responsibility to act. We must move immediately to pass legislation to END birthright citizenship and protect America’s sovereignty.”
The Decision
The ruling in Trump v. Barbara was authored by Chief Justice John Roberts, joined by Justices Brett Kavanaugh, Amy Coney Barrett, Sonia Sotomayor, Elena Kagan, and Ketanji Brown Jackson. It affirmed that children born in the United States to parents who are present illegally or on temporary visas are “subject to the jurisdiction” of the United States under the Fourteenth Amendment and are therefore citizens at birth — a principle Roberts traced to English common law, through the post-Civil War ratification of the Fourteenth Amendment in 1868, and through the Supreme Court’s own 1898 ruling in United States v. Wong Kim Ark.
The ruling struck down Trump’s Executive Order 14160, signed on his first day back in office, which directed federal agencies to deny citizenship documentation to children born in the United States if neither parent was a citizen or lawful permanent resident. Multiple federal courts had blocked the order from taking effect, and the Supreme Court’s decision Tuesday constitutes a final, binding rejection of the administration’s constitutional theory.
Miller: Congress Must Fill the Void
Rep. Miller, who represents Illinois’s 15th Congressional District and is a member of the House Freedom Caucus, the House Committee on Agriculture, the House Committee on Education and Workforce, and the House Administration Committee, has long aligned herself with the most conservative wing of the Republican Party on immigration and constitutional questions. Miller has been a vocal supporter of Trump’s immigration agenda across his second term, championing legislation to safeguard what she calls the integrity of American citizenship.
In February 2026, Miller voted to pass the SAVE America Act, which she described as essential to ensuring that “only U.S. citizens can register and vote in federal elections” — legislation she characterized as a matter of election integrity and national sovereignty. “Congress has a constitutional responsibility to secure our elections and ensure the voices of American voters are protected,” Miller said at the time.
On immigration more broadly, Miller’s record reflects a consistent position that the American immigration system has been exploited and that Congress must act aggressively to restore sovereign control over who qualifies for the rights and protections of American citizenship.
The Broader Congressional Response
Miller was not alone in her frustration Tuesday. Across the Republican conference, members echoed her call for congressional action in the immediate aftermath of the ruling. Following the decision, President Trump posted on Truth Social that while the ruling was “too bad for our Country,” Congress could remedy the situation through legislation rather than a constitutional amendment. “No long and unwieldy Constitutional Amendment is necessary! Congress should start TODAY to work on ending expensive and unfair to our Country, Birthright Citizenship,” Trump wrote. “They will have my Complete and Total Support!”
Sen. Lindsey Graham (R-SC) pledged to make restricting birthright citizenship a top priority as chairman of the Senate Judiciary Committee. Sen. Eric Schmitt (R-MO) announced he was introducing a constitutional amendment on the day of the ruling. White House Deputy Chief of Staff Stephen Miller called the decision “one of the most destructive and outrageous decisions in the long history of the Supreme Court,” adding that “American citizenship is not the birthright of the world. It belongs only and solely to Americans.”
In dissent, Justice Clarence Thomas argued the Fourteenth Amendment was “designed and understood to secure equal rights for the freed blacks” and was not intended to extend universal birthright citizenship to the children of those with no permanent connection to the United States. Justice Samuel Alito separately warned that the ruling “preserves a powerful incentive to enter or remain in this country illegally.”
What Miller and Republicans Face
Whether Congress can legislatively restrict birthright citizenship without amending the Constitution is a question the Supreme Court’s majority opinion makes difficult to answer affirmatively. While Justice Kavanaugh’s concurring opinion, which found the executive order violated federal statute rather than the Constitution, has been cited by some Republicans as preserving a legislative path, most constitutional scholars argue the majority opinion forecloses statutory restriction and that any lasting change would require a constitutional amendment — a process requiring two-thirds approval in both chambers of Congress and ratification by 38 states.
For Rep. Miller, those obstacles do not appear to be deterrents. Her call for Congress to “move immediately” reflects the urgency that House conservatives have attached to the issue since Trump first raised it as a priority — and a determination, shared broadly within the Republican conference, to keep fighting even after the Supreme Court’s definitive ruling on Tuesday.