Connecticut was among 18 states to jointly sue President Donald J. Trump on his second day in office Tuesday over his effort to deny the birthright citizenship ensconced in the Constitution and affirmed by the U.S. Supreme Court. The lawsuit filed in U.S. District Court in Boston accused Trump of a “flagrantly unlawful attempt to strip hundreds of thousands American-born children of their citizenship based on their parentage.” In the 150 years since the adoption of the 14th Amendment, courts have accepted its plain-language meaning: “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States.” One of the executive orders Trump signed Tuesday night asserts a novel interpretation of the jurisdiction clause, which long had been accepted as narrowly applying to children of foreign diplomats born in the U.S. Trump says the clause allows him to deny birthright citizenship to the children of non-citizens in certain circumstances: A baby born to a mother who is in the U.S., lawfully or not, without permanent resident status would be denied unless the father was a citizen or permanent resident. The order was titled “Protecting the Meaning and Value of American Citizenship.” The lawsuit filed by the 18 state attorneys general, as well as cities of San Francisco and Washington, D.C., was one of three filed in opposition to the order. They are the first shots in what is expected to be a war of litigation. The American Civil Liberties Union and other advocates sued on behalf of several immigrant groups in U.S. District Court in New Hampshire. The attorney general of Washington state filed another action in federal court in Seattle, joined by three other states. The multistate suit involving Connecticut seeks an injunction barring the enforcement of Trump’s prospective order, which applies only to babies born after Feb. 17 — 30 days after the signing. Connecticut’s attorney general, William Tong, said the birthright order was an irresistible target for obvious reasons: Trump’s order flies in the face of the plain meaning of the 14th Amendment and a U.S. Supreme Court decision in 1898 affirming that babies born on American soil are American, regardless of the citizenship status of their parents. “There’s no doubt. There’s no ambiguity. Black and white, the language is clear,” Tong said Tuesday. “This is not a matter of statutory interpretation.” Absent from Trump’s order is a legal rationale some conservative lawyers have offered for a way around the 14th Amendment: an assertion that America is under invasion from immigrants, even if some are coming ashore with visas. One of Trump’s judicial nominees, James C. Ho, who was a year ahead of Tong at the University of Chicago Law School, defended birthright citizenship as constitutionally protected in a 2006 article.  Ho, a Texas conservative appointed to the U.S. Court of Appeals for the 5th Circuit in 2018, offered a more sympathetic take on Trump’s invasion theory in an interview a week after Trump’s election in 2024. “Everyone agrees that birthright citizenship doesn’t apply to the children of lawful combatants. And it’s hard to see anyone arguing that unlawful combatants should be treated more favorably than lawful combatants,” Ho said. Tong said Ho and Trump are pushing against more than a century of precedent. Tong, a Chinese-America born in Hartford to parents in the U.S. with green cards making them permanent residents, said the practical harms of Trump’s order rival the constitutional ones.  “So if the baby gets sick, are you going to go to the emergency room and risk exposing your family?” Tong said. “Will anybody care for your child because the child has no status? Will you call the police? Will you call 911 if there’s an emergency at your house?” The constitutional implications are broader than the single order in citizenship, Tong said. Trump is trying change a constitutional right by a unilateral order and a flourish of his black sharpie pen, Tong said. Attorney General William Tong explaining the legal challenged filed Tuesday to the president’s executive order on birthright citizenship. Credit: mark pazniokas / crtmirror.org “This is a fundamental right enshrined in our Constitution for more than 150 years, and it would be akin to saying on other fundamental rights, ‘People may have them, it may be ensconced in the Constitution, but they don’t apply to you.’ Can you imagine?” he said. Tong quoted Ronald Reagan, the Republican president who personified the modern GOP before the rise of Donald Trump, in arguing that birthright citizenship, while not unique to the U.S., is inherent to what it means to be an American. In 1989, Reagan noted that citizenship and identity in Germany and Japan are denied to the children of recent arrivals, unlike the longstanding practice in America. “And he said, ‘This, I believe is one of the most important sources of America’s greatness.’ And that is as true today as it was in 1989,” Tong said. Gov. Ned Lamont, a Democrat who attended Trump’s inauguration, said he thought birthright citizenship was resolved in 1868 with the adoption of the 14th Amendment. He fears other conflicts with Trump over immigration. “I have a ton of concerns,” Lamont said Tuesday. Prime among them, he said, is the Trump administration moving to deport the “Dreamers,” the immigrants brought to America without legal status as young children and now are young adults who have known no other home. They were not addressed in the first round of executive orders.