Donald Trump used an expletive to attack Joe Biden during an address to an influential gun group Saturday, while the incumbent president warned in the crucial swing state of Georgia that his “unhinged” challenger is a threat to US democracy.

The dueling events came as Trump sought to make the most of his limited time on the campaign trail, with a criminal trial over hush money payments to a porn star keeping him mostly confined to a gloomy New York courtroom.

In a 90-minute rambling address to the politically powerful National Rifle Association, Trump said Biden is “the worst president in the history of our country by far” and suggested the Democrat was “full of bullshit.”

“You’re fired, get out of here Joe!” he called out to laughter from the thousands-strong crowd in Dallas, Texas, where the NRA gave the 77-year-old
Republican its endorsement in the White House race.