Shulkin had been under fire for a European trip that included a tennis outing at Wimbledon, accounts of troubling conditions at medical facilities, reports of tension with his senior staff, and friction over plans to shift care to the private sector.

'Toxic' environment

Shulkin had harsh words for his critics in a New York Times op-ed published Wednesday, framing his departure as the result of a fierce debate over privatizing VA health services. Rivals in the Trump administration "saw me as an obstacle to privatization who had to be removed," he wrote.

In recent months, "the environment in Washington has turned so toxic, chaotic, disrespectful and subversive that it became impossible for me to accomplish the important work that our veterans need and deserve."

"It should not be this hard to serve your country," he concluded.

Senate confirmation

Trump announced Shulkin's ouster in a tweet.

"I am pleased to announce that I intend to nominate highly respected Admiral Ronny L. Jackson, MD, as the new Secretary of Veterans Affairs," Trump said. "I am thankful for Dr. David Shulkin's service to our country and to our GREAT VETERANS!"

Jackson, a naval officer, has been a White House physician since George W. Bush's presidency. His nomination will require approval in the Republican-controlled Senate.

A Democrat on the Senate Veterans' Affairs Committee said Thursday that Jackson will be "scrutinized very closely" during the confirmation process.

The VA "is a sprawling bureaucracy," Richard Blumenthal of Connecticut said on MSNBC, likening the nomination to asking someone who has never climbed a mountain to start with Mount Everest. "I will have some tough questions for him."

Trump's health

Jackson conducted Trump's first official medical exam as president in January and declared Trump "fit for duty."

Questions about Trump's fitness for office had flared at the time after a book — "Fire and Fury" by Michael Wolff — asserted that many of Trump's senior aides thought the president mentally unwell. Jackson reported that a screening of the president's cognitive function, designed to check for signs of dementia or Alzheimer's disease, was normal.

Trump likes Jackson, whom Shulkin had recommended an undersecretary post at the VA last fall, according to a White House official, who added that the president realized he had a deep command of veterans issues.

Another advantage for Jackson: He has a very high security clearance because of his regular proximity to the president and his access to Trump's full health history, said two people familiar with the matter. Anyone named as head of the Department of Veterans Affairs would be required to have that kind of clearance. Jackson also has the tremendous responsibility of safeguarding the health of the commander in chief.

All three people requested anonymity to discuss administration deliberations.

Shulkin's travel

Shulkin came into office with a pledge to bring greater accountability to the agency and to improve veterans' access to care, and not to privatize the department.

In July 2017, he traveled to Denmark and England with senior Veterans Administration officials, his wife, and a six-member security detail, according to a February report by the agency's inspector general. The 11-day trip included three and a half days of official events and cost at least $122,334, the report said. It found that Shulkin improperly accepted two tickets to the ladies' final match at Wimbledon.

Shulkin told lawmakers that he regretted decisions "that have been made that have taken the focus off" the VA's work, and said he would reimburse costs as recommended by the inspector general, who called for repayments for the Wimbledon tickets and the airfare for the secretary's wife.

Cabinet scrutiny

Shulkin's trip was among several involving top Trump administration officials to draw notice. Environmental Protection Agency Administrator Scott Pruitt relied on first-class flights, racking up a $1,641.43 bill for a trip between Washington and New York, and Health and Human Services Secretary Tom Price stepped down over flights with a total cost that exceeded $1 million.

The report of Shulkin's travel stoked tensions within the agency, and he reduced contacts with Trump's political appointees and installed an armed guard outside his office, according to a March 9 report in the Washington Post. The discord centers around plans to direct more spending on veterans' care to private facilities than Shulkin favors, according to a Feb. 16 ProPublica report. On March 7, the VA inspector general released a report that said "failures in leadership" led to critical deficiencies at the agency's Washington medical center, where inventories weren't properly maintained and patient records weren't securely stored. At times, doctors had to borrow supplies from a nearby hospital, according to the report. Shulkin told interviewers he didn't recall senior officials bringing the center's problems to his attention when he was undersecretary overseeing medical facilities, according to the report.

Asked about the report, White House press secretary Sarah Sanders on March 7 said Shulkin "has done a great job."

Robert Wilkie, currently the undersecretary of for Personnel and Readiness at the Defense Department, will serve as acting secretary for Veterans Affairs while Jackson awaits Senate confirmation, Trump said.

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