The Government Accountability Office has concluded that President Donald Trump violated the law when he withheld $400 million in military aid for Ukraine.
The aid is one of the Democrat's main arguments for impeachment proceedings, which began when Democrats accused President Trump of using his office to ask for a personal favor from Ukrainian President Zelensky to investigate Joe Biden's son in a phone call.
Democrats also allege that Trump postponed nearly $400 million in military aid to Ukraine to force Zelensky to launch the investigations.
While Republicans defended the decision by saying the money was being withed while they determined whether the newly-elected Zelensky could be trusted, the watchdog concluded this week that the appropriation was a violation of the law.
In a decision released on Thursday, the nonpartisan U.S. Government Accountability Office said: "In the summer of 2019, the Office of Management and Budget (OMB) withheld from obligation funds appropriated to the Department of Defense (DOD) for security assistance to Ukraine."
"Faithful execution of the law does not permit the president to substitute his own policy priorities for those that Congress has enacted into law. OMB withheld funds for a policy reason, which is not permitted under the Impoundment Control Act (ICA). The withholding was not a programmatic delay. Therefore, we conclude that OMB violated the ICA."
"An appropriations act is a law like any other; therefore, unless Congress has enacted a law providing otherwise, the president must take care to ensure that appropriations are prudently obligated during their period of availability."
The decision concludes: "The Constitution grants the president no unilateral authority to withhold funds from obligation."
It adds that if President Trump wanted to withhold the funds he would need to notify Congress and "provide detailed and specific reasoning to justify the withholding."
The Office of Management and Budget, which withheld the money, disagreed with the findings, sating: "We disagree with GAO's opinion. OMB uses its apportionment authority to ensure taxpayer dollars are properly spent consistent with the president's priorities and with the law."
A senior official told NBC News that the findings "are a pretty clear overreach as they attempt to insert themselves into the media’s controversy of the day" and predicted the agency would have to reverse itself.
“GAO’s opinion would force agencies to spend appropriated funds as quickly as possible, before a thoughtful policy process could be completed," the official said. "This opinion stretches the legal requirements of the ICA, and following it would be irresponsible."
The finding will likely add even more fuel to impeachment proceedings, on the same day that the House passed the articles of impeachment to the Senate.
Later today, all 100 senators will be sworn in to serve as silent jurors in President Trump's trial. Chief Justice John Roberts, overseeing the trial, will also be sworn in.
Seven House impeachment managers are ceremonially read aloud the House resolution that was passed on Wednesday, officially transferring the articles of impeachment over to the Senate.
Democratic Senators reacted to the GAO's findings by saying that it "demonstrates, without a doubt, that the Trump Administration illegally withheld assistance from Ukraine and the public evidence shows that the president himself ordered this illegal act."
House Speaker Nancy Pelosi told reporters: "The OMB, the White House, the administration — I'm saying this — broke the law. She added that the findings showed Trump's "tangled web to deceive."