Retired Gen. Stanley McChrystal said Sunday that he believes President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE is "immoral," and that he would not join the administration if asked.

"It’s important for me to work for people who I think are basically honest, who tell the truth as best they know it," McChrystal said on ABC's "This Week."

"I don’t think he tells the truth," he added.

McChrystal, who resigned as the nation’s top military commander in Afghanistan in 2010 after critical remarks he made about Vice President Joe Biden Joe BidenPelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Hillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns Fox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio MORE and other civilian leaders were published in Rolling Stone, said he believes each American has to make their own judgment about whether to support Trump.

ADVERTISEMENT

"What I would ask every American to do is stand in front of that mirror and say, 'what are we about?' " McChrystal said. "Am I really willing to throw away or ignore some of the things that people do that are pretty unacceptable normally just because they accomplish certain other things that we might like."

NEW: Retired Gen. Stanley McChrystal says if asked, he wouldn't join the Trump administration because "it's important for me to work for people" who are "basically honest."@MarthaRaddatz: "Is Trump immoral in your view?"



McChrystal: "I think he is." https://t.co/WDKmB6eACk pic.twitter.com/9lmWDFcd6L — This Week (@ThisWeekABC) December 30, 2018

McChrystal has been critical of Trump's policies during his time in the White House. He questioned Trump's decision to send troops to the southern border and has expressed concern over the president's repeated criticism of former military leaders.

Trump is in search of a new full-time leader of the Department of Defense after Secretary James Mattis James Norman MattisBiden courts veterans amid fallout from Trump military controversies Trump says he wanted to take out Syria's Assad but Mattis opposed it Gary Cohn: 'I haven't made up my mind' on vote for president in November MORE resigned earlier this month. Mattis intended to remain on through February, but Trump later forced Mattis to leave at the start of 2019.

Trump said Mattis’s deputy, Patrick Shanahan Patrick Michael ShanahanHouse Armed Services chairman expresses confidence in Esper amid aircraft carrier coronavirus crisis Boeing pleads for bailout under weight of coronavirus, 737 fallout Esper's chief of staff to depart at end of January MORE, will serve as acting Pentagon chief.