The ruling is the second decision by a federal court that allows the president to be sued, according to The Associated Press. He twice failed to have a Maryland federal court lawsuit thrown out, where the state's attorney general and his District of Columbia counterpart claim President Trump is illegally taking payments from foreign and state governments at his Washington hotel.
"This is a bombshell victory enabling us to move forward to hold the president accountable for violating the chief corruption prohibition in the United States' Constitution", Blumenthal told the AP.
The Justice Department said it expects the case to be dismissed.
The Democrats' effort is led by Sen.
"The Clause requires the President to ask Congress before accepting a prohibited foreign emolument", Sullivan wrote.
Trump began his presidency by choosing - unlike other presidents in recent decades - to keep ownership of his businesses. Richard Blumenthal of CT and Democratic Rep. Jerrold Nadler of NY, had standing to sue Trump because he did not ask Congress before accepting anything that could be considered a foreign emolument.
The Trump Organization did not immediately respond to a request for comment. The lawsuit alleges that Trump, by continuing to do business with foreign governments while in office, violates the Constitution's emoluments clause.
Foreign government guests have frequently stayed at the Trump hotel in Washington. "Judge Sullivan correctly reviewed the Supreme Court and D.C. Circuit case law in this area, and concluded that President Trump harms members of Congress by accepting benefits from foreign governments without first obtaining their affirmative consent", the organization said.
Senators Richard Blumenthal (D-CT) and Representative Jerry Nadler (D-NY) are the leading plaintiffs in the case, backed by some 200 other members of Congress. His ruling does not mean that Trump violated the Constitution.
"Accordingly, if these plaintiffs do not have standing to bring their claims to address their alleged injury, it is unlikely that another plaintiff would, rendering the Clause unenforceable against the President except via impeachment", Sullivan wrote.
PHOTO: Republican presidential nominee Donald Trump and his family (L-R) son Donald Trump Jr, son Eric Trummp, wife Melania Trump and daughters Tiffany Trump and Ivanka Trump at the new Trump International Hotel, Oct. 26, 2016, in Washington, DC. Justice Department lawyers in that case say the president is not breaking the law when foreign officials book rooms at his hotel in the capital because he is not trading favors in exchange for a benefit.
A federal judge in Maryland allowed that case to move forward in July. The Justice Department, however, has asked for an appeal in that case and for all proceedings to halt until an appeals court rules.