LAS VEGAS >> A longtime columnist for The Las Vegas Review-Journal has resigned, becoming the latest journalist to leave the newspaper since it was bought by Sheldon Adelson, the billionaire casino magnate and Republican donor, late last year.

The columnist, John L. Smith, said Tuesday in a letter, several copies of which were distributed in the newsroom, that “recent events have convinced me that I can no longer remain employed at The Las Vegas Review-Journal.” Smith has been barred from writing about Adelson and was recently told that he could not write about Steve Wynn, another prominent casino owner, either.

Smith filed for bankruptcy in 2007 while defending himself against a libel lawsuit brought by Adelson, who alleged that Smith’s book “Sharks in the Desert: The Founding Fathers and Current Kings of Las Vegas” was defamatory. Adelson, who was being represented by the prominent lawyer Martin D. Singer, eventually dropped the case. In 2013, Smith wrote on The Daily Beast website that Adelson had “sued me into bankruptcy over a brief passage in my 2005 book,” adding that it was “an enormously stressful experience.”

Smith resigned just days after he became the subject of discussion at a Society of Professional Journalists meeting. During the meeting Saturday, a video of which was obtained by The New York Times, J. Keith Moyer, the newspaper’s editor, said, “I personally think it was a conflict for John to write about Sheldon.”

“I think sometimes when you have that kind of deep animosity, that it was problematic for John to be writing about Sheldon Adelson,” Moyer said, adding, “As long as I’m editor, John won’t write about Sheldon Adelson.”

Moyer said in a telephone interview that the decision to prohibit Smith from writing about Adelson was made in late January, before he became editor.

“The decision was made before I was hired. I just happened to agree with it,” he said. “People can disagree with me, but it was a call I made.” He added that Adelson “had nothing to do with this decision.”

In his letter, Smith wrote: “If a Las Vegas columnist is considered ‘conflicted’ because he’s been unsuccessfully sued by two of the most powerful and outspoken players in the gaming industry, then it’s time to move on. If the Strip’s thin-skinned casino bosses aren’t grist for commentary, who is?”

Smith did not immediately respond to a request for comment.

Several journalists have left since Adelson bought the newspaper for $140 million through a shell company, including Michael Hengel, the newspaper’s editor, who quit less than two weeks after the purchase. James Wright, a deputy editor, has received a Knight-Wallace journalism fellowship at the University of Michigan. His project title is “How Megadonors in U.S. Politics Influence U.S. Foreign Policy.”