An Asia analyst who criticized President Trump during the 2016 campaign was forced to withdraw from the position of heading a Pentagon-funded think tank in Hawaii. (Staff/AFP/Getty Images)

Patrick Cronin, a widely respected Asia analyst who had been selected to run a Pentagon-funded think tank, turned down the position under pressure because he had signed a letter last year opposing President Trump’s candidacy, according to U.S. officials and others familiar with the matter.

Cronin was chosen to oversee the Daniel K. Inouye Asia-Pacific Center for Security Studies in Hono­lulu on Jan. 17, three days before Trump assumed the presidency. His forced withdrawal is unusual because the position is not a political appointment.

Cronin was selected to run the Asia-Pacific Center by a three-member panel that consisted of representatives from the U.S. military and the Pentagon’s civilian leadership.

Senior Pentagon officials had come to see the center as an expensive and under­utilized asset that offered non-accredited graduate-level classes but produced little research.

Cronin’s mandate was to overhaul the institution and turn it into “a real thought center” that would produce valuable research that could help drive policy decisions in Washington, said a U.S. official involved in the planned overhaul.

The shake-up alarmed some long-term staff members, who feared that they might be pushed out of their positions at the policy center.

“There are a lot of career people in the Pentagon and the White House, and right now they’re wondering where does it stop?” said Kelly E. Magsamen, a former Pentagon official in the Obama administration who headed the search process that led to Cronin’s selection. “Where does it stop in terms of filtering?”

Some mid-level career bureaucrats on the National Security Council have in recent months been questioned about old posts on their social-media accounts that seemed to criticize the president, according to U.S. officials who spoke on the condition of anonymity to discuss the internal workings of the White House. But none of those officials have been disciplined or moved from their positions.

Until last week, Cronin’s position had been held up as part of a broad hiring freeze imposed by the Trump administration. In mid-March, senior Pentagon officials approved a waiver that would have allowed Cronin to assume the job.

Cronin, a Republican who has worked closely with national security adviser H.R. McMaster, was preparing for the move to Hawaii when an article in the Washington Times described him as a “liberal” and noted that he was among 122 Republican national security officials who had signed a letter opposing then-candidate Trump.

Shortly after the article appeared, Cronin said he was no longer interested in accepting the position and cited personal reasons for his withdrawal. People close to Cronin said he was pressured to not take the job. Cronin, who runs the Asia-Pacific Security Program at the Center for a New American Security, declined to comment.

The White House did not respond to questions about Cronin’s decision to withdraw from the job.

Pentagon officials said Defense Secretary Jim Mattis became aware of the controversy only after the Washington Times report.

“Secretary Mattis was not involved in the hiring decision, and he was not involved with Mr. Cronin withdrawing,” said Navy Capt. Jeff Davis, a Pentagon spokesman.