IT HAS been almost a year and a month since Seth Rich was killed in what D.C. police believe was a botched robbery attempt. In that time, the family of the 27-year-old Democratic National Committee staffer has had to deal not only with their private sorrow but also with nonsensical, hurtful conspiracy theories. What was bad when the rumors circulated on far-right websites became worse when a major news organization tried to peddle the bogus story. And that may not be the worst of it — if allegations of White House involvement prove true.

A lawsuit filed this week alleges that Fox News Channel collaborated with a wealthy supporter of President Trump and the White House to create a story published online in May — and since discredited — buttressing wild theories that Rich had leaked Democratic Party emails and was killed by operatives working on behalf of Hillary Clinton. The lawsuit by Rod Wheeler, a former Fox News contributor involved in the May report who says he was defamed, claims the White House — perhaps Mr. Trump personally — was monitoring and encouraging the story’s development.

Defendants named in the suit, including Dallas investor Ed Butowsky, who is depicted as playing a major role, denied the claims. White House press secretary Sarah Huckabee Sanders in a Tuesday news briefing said Mr. Trump “had no knowledge of the story” and claimed “it’s completely untrue that he or the White House had involvement in the story.”

Skepticism is always in order when viewing the allegations of a lawsuit, and issues have been raised about Mr. Wheeler’s credibility because he helped to further the discredited story. But, as reported by NPR’s David Folkenflik, Mr. Wheeler has marshaled documentary evidence (including text messages and recorded phone calls) that bolster his account. “Not to add any more pressure but the president just read the article. He wants the article out immediately. It’s now all up to you,” reads a May 14 text from Mr. Butowsky to Mr. Wheeler. The story appeared about 36 hours later. Mr. Butowsky told reporters this week he was joking.

Particularly troubling is that on April 20, a month before the discredited story ran, Mr. Butowsky and Mr. Wheeler met at the White House with then-press secretary Sean Spicer to brief him on the story’s development. After the story broke, Mr. Spicer played dumb. “I’m not aware . . . generally I don’t get updates on DNC — former DNC staffers,” Mr. Spicer said May 16 when questioned by reporters.

It is sad that the White House track record for honesty is such that allegations that should be preposterous can’t easily be dismissed. Even sadder is the thought that American political life has sunk so low that the truth and a family’s pain may be seen as minor obstacles to be brushed out of the way.