Washington • Mick Mulvaney, the acting White House chief of staff, threw the Trump administration’s defense against impeachment into disarray Thursday when he said that the White House withheld nearly $400 million in military aid to Ukraine to further President Donald Trump’s political interests.

Mulvaney told journalists in a televised White House briefing that the aid was withheld in part until Ukraine investigated an unsubstantiated theory that Ukraine, not Russia, was responsible for hacking Democratic Party emails in 2016 — a theory that would show that Trump was elected without Russian help.

The declaration by Mulvaney, which he took back later in the day, undercut Trump’s repeated denials of a quid pro quo that linked American military aid for Ukraine to an investigation that could help Trump politically.

The comments sent Washington into turmoil as Democrats and some Republicans said they were deeply damaging to Trump.

At the White House, Mulvaney said that Trump had demanded that Ukraine investigate the theory, even though a former White House homeland security adviser had told Trump that the theory had been completely debunked.

“The look back to what happened in 2016 certainly was part of the thing that he was worried about in corruption with that nation,” Mulvaney told reporters, referring to Trump. “And that is absolutely appropriate.”

Mulvaney’s acknowledgment of a tie between military aid and a political investigation came as House Democrats were summoning a stream of witnesses to the Capitol to investigate whether Trump had pressured Ukraine for his personal political benefit in 2020.

Democrats called Mulvaney’s comments a potential turning point in their impeachment inquiry. “We have a confession,” said Rep. Eric Swalwell, D-Calif.

By day’s end, after Trump told aides to clean up the mess, Mulvaney issued a statement flatly denying what he had earlier said.

“Once again, the media has decided to misconstrue my comments to advance a biased and political witch hunt against President Trump,” Mulvaney wrote. “Let me be clear, there was absolutely no quid pro quo between Ukrainian military aid and any investigation into the 2016 election. The president never told me to withhold any money until the Ukrainians did anything related to the server.”

But in his earlier remarks to reporters, Mulvaney pointed to “three issues” that explained why officials withheld the aid: corruption in Ukraine, frustration that European governments were not providing more money to Ukraine and the president’s demand that Kyiv officials investigate the issue of the Democratic National Committee server.

“Did he also mention to me in passing the corruption related to the DNC server?” Mulvaney said, referring to Trump. “Absolutely. No question about that.” He added: “That’s why we held up the money.”

Democrats ridiculed the reversal.

“Mick Mulvaney was either lying then, or he’s lying now,” said Rep. Ted Lieu, D-Calif., who is involved in the inquiry. “I think he’s lying now.”

At the White House, staff members recognized that Mulvaney had created an entirely new controversy with his remarks. Jay Sekulow, one of Trump’s personal lawyers, said Thursday, “The president’s legal counsel was not involved in acting chief of staff Mick Mulvaney’s press briefing.”

Mulvaney’s performance was only part of another extraordinary day in Trump’s presidency. Mulvaney made his remarks after he stepped before the cameras to announce that leaders of the Group of 7 nations would meet in June at Trump’s golf resort in South Florida, even as he acknowledged the choice could be seen as self-enrichment. In Texas, Trump hailed a Middle East cease-fire that would cement Turkey’s goal of pushing Kurds from northern Syria as “a great day for civilization.”

And on Capitol Hill, Gordon Sondland, the president’s ambassador to the European Union and a wealthy donor to Trump’s campaign, was implicating the president in the Ukraine scandal by telling lawmakers that Trump had delegated Ukraine policy to his personal lawyer Rudy Giuliani.

Sondland testified behind closed doors for more than six hours, the latest in a series of current and former diplomats and White House aides who have provided detailed accounts of actions by Giuliani and others related to Ukraine.

Democratic lawmakers are certain to seize on Mulvaney’s comments as crucial support of the testimony coming from other witnesses, who have accused the administration of improperly pressuring Ukraine and of sidelining veteran diplomats in favor of Trump’s political loyalists.

But Mulvaney was defiant and unapologetic at the suggestion that there was anything wrong with the president’s relying on political loyalists to conduct foreign policy.

“I have news for everybody: Get over it. There’s going to be political influence in foreign policy,” he said, adding, “Elections have consequences.”

In wide-ranging remarks, Mulvaney told reporters at the White House that the $391 million in military aid was initially withheld from Ukraine because the president was displeased that European countries were not as generous with their assistance. He also wanted more attention paid to Ukraine’s persistent political corruption.

Mulvaney denied that the aid for Ukraine was also contingent on its government opening an investigation into either former Vice President Joe Biden, a leading Democratic candidate for president, or his younger son, Hunter Biden. Asked whether he did anything to pressure President Volodymyr Zelenskiy of Ukraine to investigate the Bidens, Mulvaney said no.

But the president did pressure Ukraine to reexamine discredited theories that Ukraine, not Russia, had worked to sway the 2016 campaign. Mulvaney’s mention of a “DNC server” was a reference to an unfounded conspiracy theory promoted by Trump that Ukraine was somehow involved in Russia’s 2016 theft of emails from the Democratic National Committee and the Democratic Congressional Campaign Committee.

Mulvaney tied the server to the Justice Department’s review of the origins of the Russia investigation, led by the U.S. attorney in Connecticut, John H. Durham, and closely overseen by Attorney General William Barr.

“That’s an ongoing investigation,” Mulvaney said. “So you’re saying the president of the United States, the chief law enforcement person, cannot ask somebody to cooperate with an ongoing public investigation into wrongdoing? That’s just bizarre to me that you would think that you can’t do that.”

But while the Justice Department said last month that Durham is examining any role that Ukraine might have played in the early stages of the Russia investigation, a department official declined Thursday to comment on whether he is examining the server conspiracy theory.

Russian military officers hacked Democratic servers to steal thousands of emails in 2016, the intelligence community and the special counsel found, and no one has uncovered evidence of Ukrainian involvement.

Justice Department officials were confused and angry when they heard that Mulvaney said the White House had frozen aid to Ukraine in exchange for help with the Durham investigation, according to a person familiar with their discussions.

“If the White House was withholding aid in regards to the cooperation of any investigation at the Department of Justice, that is news to us,” a senior Justice Department official said. Durham was seen leaving the Justice Department around midday Thursday.

Mulvaney said the president had done nothing improper and had stayed within normal diplomatic channels. He blasted the current and former administration officials who have testified in the impeachment inquiry, describing them as personally opposed to the changes in foreign policy that Trump had put in place.

“What you’re seeing now, I believe, is a group of mostly career bureaucrats who are saying, ‘You know what, I don’t like President Trump’s politics, so I’m going to participate in this witch hunt that they are undertaking on the Hill.’”

Mulvaney said holding up Ukraine’s aid was a normal part of foreign policy, and he compared it to the foreign aid to Central America that the administration froze until Guatemala, El Salvador and Honduras agreed to adopt the immigration policies pressed by Trump.

Asked whether he had admitted to a quid pro quo, Mulvaney said: “We do that all the time with foreign policy."

His answer ignored the distinction — raised by many of the president’s critics — between holding up foreign aid to further American interests and holding up foreign aid to further Trump’s personal interests.

Senior White House aides like Mulvaney are often largely immune from congressional subpoenas to discuss their private conversations with the president, but talking about them publicly in such an extended way could undermine that legal protection.

Democrats had already been interested in Mulvaney’s role in the Ukraine matter after several impeachment witnesses described him as a central player in the effort to hold up the aid in the days before Trump pressed Ukraine’s president to investigate Biden.

They also have said they want to know whether Mulvaney helped prevent a White House meeting between Trump and Zelenskiy until the Ukrainian government agreed to investigate the president’s rivals, including the DNC and the Bidens.

Fiona Hill, the president’s former senior director for European and Russian affairs at the National Security Council, testified that Mulvaney was part of a trio of Trump loyalists who conducted a rogue foreign policy operation in Ukraine.

Hill told lawmakers that John R. Bolton, then the national security adviser, instructed her in early July to advise the National Security Council’s chief lawyer about the effort by Mulvaney, Sondland and Giuliani.

“I am not part of whatever drug deal Sondland and Mulvaney are cooking up,” Bolton told Hill to tell White House lawyers, according to two people at Hill’s deposition, which took place Monday.

In his remarks Thursday, Mulvaney said there is nothing wrong with Trump relying on Giuliani or others outside of the diplomatic corps to conduct foreign policy.

“That’s the president’s call,” he said. “You may not like the fact that Giuliani was involved. That’s great, that’s fine. It’s not illegal, it’s not impeachable.” He added that “The president gets to set foreign policy and he gets to choose who to do so.”

Democrats are also eager to know about a May 23 meeting during which career diplomats with responsibility for Ukraine were sidelined in favor of Sondland; Kurt Volker, the special envoy for Ukraine; and Rick Perry, the energy secretary, one witness testified.

George Kent, the deputy assistant secretary in the Bureau of European and Eurasian Affairs, testified Tuesday that Mulvaney called the White House meeting, according to Rep. Gerald E. Connolly, D-Va., who was in the room for Kent’s testimony.