A committee of media lawyers at the American Bar Association commissioned a report on Donald Trump’s history of filing lawsuits to punish and silence his critics, concluding that Mr. Trump was a “libel bully” who had filed many meritless suits attacking his opponents and had never won in court.

But the bar association refused to publish the report, citing “the risk of the ABA being sued by Mr. Trump.”

David J. Bodney, a former chairman of the media-law committee, said he was baffled by the bar association’s interference in the committee’s journal.

“It is more than a little ironic,” he said, “that a publication dedicated to the exploration of First Amendment issues is subjected to censorship when it seeks to publish an article about threats to free speech.”