Jackson's confirmation process is now on indefinite hold because the Senate Veterans Affairs Committee is investigating allegations he oversaw a hostile work environment as the White House physician, allowed the over-prescribing of drugs, and drank too much on the job, according to the New York Times.
The president spoke hours after Senator Johnny Isakson, chairman of the Veterans Affairs Committee, said he and the panel's ranking Democrat, Jon Tester, made a decision to delay a hearing on Jackson's nomination that had been scheduled for Wednesday and sent a letter to Trump seeking more information.
Rear Adm. Jackson, the White House physician, was nominated to lead the Veterans Affairs Department after Mr. Trump fired David Shulkin.
Looking ahead to the eventual meeting between the USA and North Korea, Mr. Trump said the North Koreans have said they want the summit to happen "very soon".
Johnny Isakson of Georgia, the chairman of the Senate's Veterans' Affairs Committee, briefed Republicans on his panel in a telephone call about some of the allegations that had surfaced against Jackson.
The Defense Department inspector general would not comment on the existence of any possible investigations into Jackson's conduct and referred all questions to the White House.
But I told Admiral Jackson just a little while ago - I said, what do you need this for?
At the time of the report, Kuhlman was the physician to the president, while Jackson was the director of the White House Medical Unit.
Sen. Jerry Moran, R-Kan., said that Jackson denied allegations of a hostile workplace while working as the White House physician, and told Moran that "he has never had a drink while on duty".More news: Everton edge past Newcastle at home
More news: Champions League: Liverpool vs Roma: Klopp sends strong message to Reds fans
More news: Toronto Maple Leafs force Game 7 with key victory over Boston Bruins
But he also acknowledged that Jackson lacked the necessary experience to run the government's second-largest bureaucracy, and he said he urged Jackson to think about whether he wanted to move forward. It demands any communication between the Pentagon and the White House for the last 12 years regarding "allegations or incidents" involving him. Jackson has served as a White House doctor since 2006.
Trump said a decision about whether to proceed would be left to Jackson. "He's served as the physician to three Presidents - Republican and Democrat - and been praised by them all".
The audit appeared to contradict public statements from Jackson, who declined Tuesday to answer reporters' questions about the allegations. "I was impressed with what he shared with me, but at the same time, you do the vetting process".
Democratic Sen. Richard Blumenthal says some Republicans have told him that they think the hearing should be postponed, which he says deserves consideration.
Asked about the allegations concerning prescription drugs, Moran said that allegation did not come up during their meeting.
He tells NPR the committee was told that Jackson was "repeatedly drunk" while on travel with former President Barack Obama and that on overseas trips Jackson improperly handed out prescription drugs to help travelers sleep and wake up. "I said, 'What do you need it for?'"
Chairman Isakson and ranking member Tester released a joint statement saying that the hearing had been postponed "in light of new information presented to the committee". "We most certainly want to get all the facts out", he said.
"We're pushing back", the official said, speaking on condition of anonymity. "But there's an experience problem - the Veterans Administration is very important to me". The report found that the conflict between them had become so bitter that workers described the dynamic as "being caught between parents going through a bitter divorce".