Scrambling Trump dusts off past arguments against Russian collusion in desperate tweets
Donald Trump speaks during a campaign rally at the American Airlines Center in Dallas on September 14, 2015 (AFP Photo/Laura Backman)

As news about his chief of staff's exit and the mounting collusion and obstruction investigations reached a head Monday, President Donald Trump decided to resurrect a favorite topic on Twitter.

"James Comey’s behind closed doors testimony reveals that 'there was not evidence of Campaign Collusion' with Russia when he left the FBI," the president tweeted -- failing to mention that Comey left his post as FBI director early in his administration because he fired him.

"In other words, the Witch Hunt is illegal and should never have been started!" Trump summarized.

He then plugged an upcoming report from Fox host Lou Dobbs about Comey.

"'Former FBI Director James Comey under fire for his testimony acknowledging he knew that the Democrats paid for that phony Trump Dossier,'" the president tweeted, tagging Dobbs and adding that more details will come on Tuesday night.