WASHINGTON — Rejecting a request from President Donald Trump, a federal judge in Washington, D.C., on Tuesday cleared the way for nearly 200 Democrats in Congress to continue their lawsuit against him alleging that his private business violates an anti-corruption provision of the Constitution.

U.S. District Judge Emmet Sullivan declined to put the case on hold and said lawmakers could begin this week seeking financial information, interviews and other records from the Trump Organization.

“This case will be poised for resolution within six months; an immediate appeal would hardly materially advance its ultimate termination,” Sullivan wrote in a 12-page ruling rejecting the president’s position.

The Trump administration still can try to delay or block Democrats in Congress from issuing subpoenas for the president’s closely held business information by appealing directly to the U.S. Court of Appeals for the D.C. Circuit to intervene.

The decision is another significant step in one of two novel cases considering the “emoluments” clauses of the Constitution, which bar the president from accepting gifts or payments from foreign or state governments.

The cases mark the first time federal judges have interpreted these clauses and applied the restrictions to a sitting president.

The “practical consequences”of the court’s orders “cannot be overstated,” Trump administration lawyers wrote, in asking for a midstream appeal before Sullivan’s final judgment.

Justice Department lawyers had asked Sullivan to take the unusual step of signing off on an immediate appeal of his earlier rulings because of the “exceptional circumstances” of the case. “Plaintiffs are now poised to seek civil discovery against the President, including into his personal finances and official actions, which will distract the President from his official duties.”

Sullivan ordered the two parties to begin the process of requesting records and other information as part of a three-month period from June 28 to Sept. 27.

The case is one in a number of disputes in which Democrats are pursuing private financial information about Trump and the Trump Organization, which the president is maintaining ownership of while in office.

In a second emoluments case, brought by the attorneys general of D.C. and Maryland, a federal judge also denied the Trump administration’s request for an immediate appeal. But the Richmond-based U.S. Court of Appeals for the 4th Circuit agreed to review the case and temporarily blocked subpoenas from the attorneys general for financial records and other documents related to Trump’s D.C. hotel.

The 4th Circuit, which reviews cases from the District of Columbia and Maryland, heard oral arguments in March, and could issue a ruling at any time.

The congressional emoluments case in Washington was initiated last year by about 200 Democrats, led by Sen. Richard Blumenthal, D-Conn., and Rep. Jerrold Nadler, D-N.Y. They want the court to order the president to stop accepting payments they consider violations of the Constitution’s foreign emoluments clause. The lawmakers and attorneys from the nonprofit Constitutional Accountability Center say the provision was designed to guard against undue influence by foreign governments by barring any “emolument” — meaning a gift or payment — without prior approval from Congress.

In September, Sullivan ruled that lawmakers had legal standing to sue and allowed the case to continue in part because the foreign emoluments clause “requires the President to ask Congress before accepting a prohibited emolument.”

Sullivan issued an additional opinion in April adopting a broad definition of “emolument” backed by the congressional Democrats.