White House national security adviser Robert C. O’Brien asserted Wednesday that President Trump had not sought Ukrainian help investigating former vice president Joe Biden and his son, Hunter, despite evidence to the contrary.

Trump expressly asked Ukrainian President Volodymyr Zelensky to “look into” the Biden family during the July 25 phone call that played a central role in House Democrats decision to impeach the president for allegedly pressuring a foreign ally to investigate his domestic political rival.

O’Brien also said the Senate impeachment trial expected to end Wednesday with Trump’s acquittal has cast “a terrible pall” that set back U.S. foreign policy.

He did not directly answer a question about whether the Trump administration will continue to seek Ukrainian investigations of the Bidens once the impeachment case is over. Joe Biden is now seeking the Democratic presidential nomination to run against Trump this year. Hunter Biden accepted a position on the board of a Ukrainian gas company while the elder Biden was vice president, a move that the president’s allies have called corrupt but that never led to any charges of wrongdoing in Ukraine.

Days away from the Senate's vote on whether to acquit President Trump, lawmakers considered what the trial would mean to the president. (The Washington Post)

“Look, I’m not aware of any request the president made to investigate the Bidens per se. I think what the president wanted done was he wanted the Ukrainians to investigate corruption in the Ukraine and he made that very clear,” O’Brien said before an audience of ambassadors and reporters at the Meridian International Center.

A White House summary of the call released in September quotes Trump as encouraging Zelensky to work with Trump’s personal attorney, Rudolph Giuliani, who has publicly accused the Bidens of corrupt activities in Ukraine, and to reopen a shuttered inquiry into the gas firm that had employed Hunter Biden. Trump also recommended that Zelensky speak to Attorney General William P. Barr.

Rudy Giuliani set out to Ukraine to vindicate the president. Instead, he helped set an impeachment scandal in motion. (Jon Gerberg, Dalton Bennett/The Washington Post)

“There’s a lot of talk about Biden’s son, that Biden stopped the prosecution and a lot of people want to find out about that,” Trump said. “So whatever you can do with the attorney general would be great. Biden went around bragging that he stopped the prosecution, so if you can look into it,” Trump said. “It sounds horrible to me.”

In addition, Trump told reporters on Oct. 3 that both Ukraine and China, where Hunter Biden also had business interests, should investigate the Bidens.

“They should investigate the Bidens,” Trump said of Ukraine. He added: “And, by the way, likewise, China should start an investigation into the Bidens, because what happened in China is just about as bad as what happened with — with Ukraine.”

The administration has not said whether that request still stands as a matter of U.S. policy toward Ukraine. Giuliani has said he will continue his efforts.

In an interview with NPR on Tuesday, Giuliani said Trump should continue pressing for an investigation after his expected acquittal.

“Absolutely, 100 percent,” Giuliani said. “I would have no problem with him doing it. In fact, I’d have a problem with him not doing it. I think he would be saying that Joe Biden can get away with selling out the United States, making us a fool in the Ukraine.”

Both Bidens deny wrongdoing and Joe Biden has said Trump and his allies have trafficked in lies and conspiracy theories surrounding his anti-corruption efforts as vice president.

In an interview after O’Brien’s address, Ukraine’s ambassador to the United States, Volodomyr Yelchenko, diplomatically declined to comment on O’Brien’s assertion.

“I was not a part of that famous conversation,” Yelchenko said of the July 25 call. “I’m not as close to President Trump as [O’Brien.] He probably knows better.”

O’Brien delivered a warm endorsement of Zelensky on Wednesday and said U.S. support for Ukraine remains strong. He urged the audience to visit Ukraine for fine food, hospitality and architecture.

“Look, Ukraine is a friend, it’s a partner,” O’Brien said. “We’re there to support Ukraine.”

Yelchenko noted, however, that O’Brien did not answer a question the ambassador had posed about whether Washington was selecting a replacement for Kurt Volker, the former special envoy for Ukraine focused on negotiations between Ukraine and Russia.

Volker resigned last fall, as Democrats were beginning what became the impeachment inquiry.

Yelchenko said that Kyiv has repeatedly pressed Washington, including when Secretary of State Mike Pompeo visited Kyiv last month, for a commitment to appoint a replacement for Volker.

“I can only say that Pompeo reacted that, ‘yes, there was an issue and we are working on that,’” Yelchenko said.

He said that there is still not agreement on a date for a White House visit by Zelensky, but that it should be part of a visit by Zelensky to the United States being planned. That visit will include a trip to Houston to open a new consulate as well as a trip to California, Yelchenko said.

The key point discussed during Pompeo’s visit, however, was the continuing U.S. military, security, economic and political assistance — especially to have more active American participation in “solving the problems caused by Russia.”

That is why the Ukrainians want a replacement for Volker as soon as possible. Yelchenko said O’Brien “is very much aware” of the issues. “I didn’t expect anything [substantive] in front of 100 ambassadors,” he said. The detail will have to come in a one-on-one meeting.

Yelchenko had said during an earlier interview with The Washington Post that when he made his first visit as ambassador to Trump last month, the president assured him that he would welcome Zelensky to the White House and they just needed to find a date.