President Donald Trump can’t get out of Congressional Democrats’ lawsuit alleging he violated the emoluments clause of the U.S. Constitution, a D.C. federal judge ruled Friday, saying the lawmakers have standing to challenge the president, and their allegations amount to more than “a political dispute between the elected branches of government.”

U.S. District Judge Emmet Sullivan’s ruling allowing the suit to move forward came down to a question of injury. The president is supposed to seek Congress’ approval when he accepts a foreign gift, and approximately 200 members of Congress argued their votes had been nullified because Trump hadn’t sought their permission.

But Trump countered that the dispute didn’t belong in court. He said Democratic lawmakers should instead convince their Republican colleagues to help pass a law to stop his alleged practice of accepting foreign gifts.

The judge came down on the side of the legislators, finding the emoluments clause gave “each individual member of Congress a right to vote before the president accepts” a gift. Depriving lawmakers of that right constituted a legitimate institutional injury under the U.S. Supreme Court’s 1997 Raines v. Byrd decision.

“That Congress acts as ‘the body as a whole’ in providing or denying consent does not alter each member’s constitutional right to vote before the president accepts a prohibited foreign emolument, because the body can give its consent only through a majority vote of its individual members,” the judge said.

The suit, filed in June 2018 by 30 members of the U.S. Senate and 166 members of the U.S. House of Representatives, is led by Sen. Richard Blumenthal, D-Conn., and Rep. Jerrold Nadler, D-N.Y. It accuses the president of violating the emoluments clause by continuing to profit from his sprawling private business, the Trump Organization, while in office. The complaint alleges the president has accepted payments, loans and regulatory actions from foreign governments without the consent of Congress.

No Republicans have signed on to the suit.

Sen. Blumenthal has said the president’s tax returns, which have been a source of controversy since early in the 2016 presidential campaign, would be among the documents federal lawmakers would seek in order to identify potential undeclared payments or benefits bestowed on the president by foreign governments.

Questions about transparency issues and potential conflicts of interest with Trump’s privately owned business first arose during the presidential campaign when then-candidate Trump refused to publicly release his tax returns, breaking with decades of tradition by presidential contenders and his own campaign-trail promises.

Those questions intensified when Trump refused to fully divest from his business when he took office in January 2017.

Trump’s U.S. Department of Justice attorneys have argued that any money the president made through his private business interests didn’t constitute gifts. The DOJ said the case should be dismissed because the emoluments claims amount to a political dispute between members of Congress, and courts have historically said those should be resolved through political mechanisms.

But Judge Sullivan called the president’s proposed legislative remedies “clearly inadequate,” noting that the Constitution already contains “unambiguous” language prohibiting the president from accepting foreign gifts without consent — which has allegedly gone ignored.

“In asking this court to accept the proposition that legislation on the emoluments issue would be an adequate remedy, the president asks this court to ignore this constitutional clause. The court may not do so,” the judge said in Friday’s order. “The president does not explain why such legislation, assuming he signed it, would prevent him from accepting prohibited foreign emoluments. His failure to explain is especially problematic given that the Constitution itself has not prevented him from allegedly accepting them.”

Judge Sullivan also acknowledged a suit in Maryland federal court focusing on alleged damages suffered by local businesses that must now compete with Trump’s properties, like his D.C. hotel, which has hosted multiple events for foreign governments. Attorneys general for Maryland and D.C. claim the venue enjoys an unfair advantage over competitors due to its ties to the president.

“That challenge seeks to remedy entirely different injuries,” Judge Sullivan said.

The president’s other arguments for dismissing the case — challenges to the suit’s jurisdiction and the possibility and constitutionality of relief — were merits questions that weren’t appropriate at this early phase of the litigation, the judge said.

Constitutional Accountability Center President Elizabeth Wydra, an attorney for the legislators, called Friday’s ruling “momentous.”

“By recognizing that members of Congress have standing to sue, the court proved to all in America today that no one is above the law, not even the president,” she said in a statement. “We look forward to making our case on the merits in coming weeks that President Trump is violating the foreign emoluments clause and must be permanently enjoined from doing so.”

Representatives for the DOJ and the White House and representatives for Sen. Blumenthal did not respond to comment requests Friday.

The plaintiffs are represented by Brianne J. Gorod, Elizabeth B. Wydra and Brian R. Frazelle of the Constitutional Accountability Center.

Trump is represented by Brett A. Shumate and Jean Lin of the DOJ’s Civil Division.

The case is Blumenthal et al. v. Trump, case number 1:17-cv-01154-EGS, in the U.S. District Court for the District of Columbia.