More than five years after a gunman murdered 20 first graders at Sandy Hook Elementary School in Newtown, Conn., their families still get daily threats and online abuse from listeners of Alex Jones, whose claim that the massacre was a hoax is one of the many bogus conspiracy theories he peddles on his InfoWars radio broadcast and website. The Times’s Elizabeth Williamson wrote a moving account of the families’ effort to hold Mr. Jones legally accountable.

People like Mr. Jones, who says 9/11 was an inside job and the government blew up the Oklahoma City federal building, have been around from the distant days when they were called “the lunatic fringe.”

Now he’s mainstream.

During the last presidential campaign, after Mr. Jones had been spouting vicious nonsense about Sandy Hook for years, Donald Trump appeared on his show to tell him: “Your reputation is amazing. I will not let you down.”

He hasn’t.

Mr. Trump, who built his political career by spreading the racist lie that President Barack Obama was not born in the United States, has kept the conspiracy theories flowing now that he’s in the White House.