Speaking at a United States Studies Center event at the University of Sydney, Mr. Howard said most criticisms of Mr. Trump came down to his “locker-room” manner, not his policy.

“You’ve got to look through the style,” Mr. Howard said. “Some of the things he has done on the international stage have been unsettling. But he’s done a number of things as president that are very praiseworthy.”

One of those things, in Mr. Howard’s view: Mr. Trump’s swift strikes on Syria in April. Mr. Howard called Mr. Trump’s handling of the Syrian conflict “outstanding.”

Last February, during Mr. Trump’s rise toward the Republican nomination, Mr. Howard said that he “trembled at the thought of Trump being president.” That trembling, it appears, has settled.

One other interesting revelation from last night was Mr. Howard’s lurch away from mainstream thinking on the climate. “I have increasingly become more of a skeptic on climate change,” he said. For critics of his refusal to sign the Kyoto Protocol, though, that might not be a revelation at all.

Mr. Howard, who led Australia into the 2003 Iraq war, has long enjoyed strong relations with the Republican Party in the United States — in particular the Bush family.