Like many social media users, Kevin Rudd, a former prime minister of Australia and its current ambassador to the United States, has posted a range of things online: a plug for his new book, cheers for his Australian rules football team and many photographs of his cats.

But some of Mr. Rudd’s posts appear to have become a liability and an unwanted distraction after the re-election of Donald J. Trump.

“The most destructive president in history,” Mr. Rudd wrote on Twitter, now X, in 2020. “He drags America and democracy through the mud.”

Mr. Rudd deleted that post, and others criticizing Mr. Trump, as the results of the election became clear on Wednesday. In a statement on his personal website, Mr. Rudd said that he had made those remarks in his capacity as a commentator on American politics and removed them “out of respect for the office of president of the United States.” He added that he did not want them to be construed as reflecting the views of the Australian government.

It remains to be seen whether Mr. Rudd’s past criticisms of Mr. Trump will affect relations between Australia and the United States, which are close allies. (Apprised of those remarks during a British television interview in March, Mr. Trump said of Mr. Rudd, “He won’t be there long if that’s the case.”)

But the deletion of the comments highlighted the sensitivities and challenges ahead for some of Washington’s closest partners in dealing with a president who has expressed antipathy for many of the foundational tenets of American alliances.