Rep. Mick Mulvaney testifies before the Senate Budget Committee on his nomination of to be director of the Office of Management and Budget.

Merkley explained that he brought it up because budgets “often contain buried deceptions.”

“This is an example of where the president’s team, on something very simple and straightforward, wants to embrace a fantasy over the reality,” Merkley said.

At one point, Oregon Sen. Jeff Merkley pulled out pictures comparing the crowds at President Barack Obama's 2009 inauguration and Trump’s own inauguration last week. He asked Mulvaney which crowd was larger based on the side-by-side photographs and Mulvaney agreed that Obama's crowd appeared larger.

South Carolina Rep. Mick Mulvaney faced questions on his commitment to telling the truth during a hearing before the Senate Committee on the Budget Tuesday, as they consider whether to approve his nomination for OMB director.

WASHINGTON — Senators grilled President Donald Trump's pick to head the Office of Management and Budget on Tuesday morning over whether he'll be able to tell the truth, and counter some of the administration's dubious "alternative facts," if confirmed.

Merkley then asked Mulvaney if he was comfortable with presenting falsehoods as "alternative facts" — a reference to the phrase Kellyanne Conway used over the weekend to defend press secretary Sean Spicer, who lied to reporters about the size of the audience for Trump’s inauguration.



In response, Mulvaney emphasized throughout the hearing his intent to use a “fact-based approach” to advise the president.

“I have every intent, and believe that I have shown up to this point in my time in Congress, that I am deadly serious about giving you hard numbers, and I intend to follow through on that,” Mulvaney responded.

Mulvaney also added in his exchange with Merkley that he believed it was his responsibility to present the president with "cogent" arguments of both sides of an issue.

Apparently not happy with Merkley's line of questioning, Republican Sen. David Perdue said, "I am thoroughly disgusted." He called the committee probably one of the most "blatantly partisan" he sits on.



But the theme of facts and the truth continued during the hearing, though none of the other senators addressed the issue as blatantly as Merkley and his photo display. Even a Republican senator, Sen. Ron Johnson, asked Mulvaney if he was dedicated to providing information and facts while questioning him on topics that included Social Security and the debt.

Democratic Sen. Tim Kaine also sent rapid-fire questions Mulvaney's way about whether he agreed with established facts on topics including the Affordable Care Act, tax breaks, and climate change.

"You deserve the truth about budget matters, as do the American people and the president, and it's the OMB director's responsibility to tell you and the president the truth, even from time to time when that might be hard to hear," Mulvaney made a point of saying during his opening remarks at the hearing.

During the hearing, Democratic Sens. Bernie Sanders and Chris Van Hollen commended Mulvaney for his reputation of being a "straight shooter," despite their objections to some of his views on policy matters.

Later in the day Tuesday, Mulvaney attended a second hearing on his nomination, this time with the US Senate Committee on Homeland Security and Governmental Affairs, where he was again pressed on whether he'll be honest with members of Congress and the public.

After repeated questioning on the issue in the Budget committee, Mulvaney started out his second hearing by outlining his commitment to facts. "Facts, and the cogent arguments of others, matter, and my commitment to you today is to take a fact-based approach and to listen to the various ideas about how to get our financial house in order."

But later in the hearing, Sen. Claire McCaskill, the ranking Democrat on the committee, took up Merkley's mantel, telling Mulvaney that she is "worried about data coming out of your shop."

"I've got to be honest with you, this is an awkward and uncomfortable line of questioning for me, but I think it's really important to put it on the record," she said. "I have been astounded over the last few days at what has occurred, that the president sent his press secretary out to utter falsehoods in a press briefing."

McCaskill also mentioned Trump advisor Kellyanne Conway's use of the term "alternative facts."

"And then, yesterday, [Trump] says he was denied the popular vote because of millions of illegal immigrants, and there is not one iota of evidence of that claim," McCaskill said. "Now, I get campaigning, I get campaign promises. But I want to ask you, congressman, if the president asks you to not issue real data or asks you to alter data according to his narrative, what would your reaction be?"

"The credibility that I think I bring to this job is that I believe very firmly in real numbers," Mulvaney replied. "My job is to tell the president the truth, my job is to tell you the truth."

McCaskill continued to press Mulvaney on the issue, asking if he would resign if the president told him "to say something other than the truth."

"I don't imagine the President of the United States would tell me to lie," Mulvaney responded.

"I beg your pardon!" McCaskill said. "He told Sean Spicer to go out there and say things that were demonstrably untrue."

"I'm not privy to the conversations between the president and Mr. Spicer so I can't comment on that," Mulvaney said. "I'm not sure if that conversation took place or not."

McCaskill told Mulvaney "you get my point," and asked again whether he would refuse to lie even under a directive from the president.

"Like I said, my in this job is my credibility when it comes to numbers," Mulvaney said. "I don't plan on exposing myself to claims of hypocrisy."

"I think that's great, and I appreciate that answer on the record," McCaskill said.

After the two hearings on Tuesday, Mulvaney will now have to wait for approval from both committees and then the full Senate before he is confirmed to run OMB. None of those votes has yet been scheduled.

The Republican took office in 2010 after being elected to the House during the tea party wave. He currently serves on the House Financial Services and the House Oversight and Government Reform committees in addition to being a member of the conservative House Freedom Caucus.



Emma Loop contributed to this report.