David Letterman thinks comedy could spark the downfall of President Donald Trump.

The 69-year-old former talk show host wishes people would stopped being shocked by the US leader's statements and instead focus on ''protecting'' themselves from him.

And David insists jokes at Trump's expense - such as Alec Baldwin's infamous 'Saturday Night Live' impressions - are the perfect way to pile on the pressure as they distract the president from other issues.

He said: ''I'm tired of people being bewildered about everything he says, 'I can't believe he said that.'

''We gotta stop that and instead figure out ways to protect ourselves from him. We know he's crazy. We gotta take care of ourselves here now.

''Comedy's one of the ways that we can protect ourselves. Alec Baldwin deserves a Presidential Medal of Freedom. Sadly, he's not going to get it from this president.

''[Trump] has such thin skin that if you keep pressure on him -- I remember there was a baseball game in Cleveland, and a swarm of flies came on the field and the batters were [swatting flies] while the pitcher was throwing 100 miles an hour.

''Well, that's Alec Baldwin and 'Saturday Night Live'. It's distracting the batter. Eventually Trump's going to take a fastball off the sternum and have to leave the game.''

While David - who quit late night TV in 2015 after 33 years - insists he has no desire to get back on screen, he admits he would love the chance to confront the president about ''lying'' and give him a ''bit of a scolding''.

He told New York magazine: ''I would just start with a list. 'You did this. You did that. Don't you feel stupid for having done that, Don? And who's this goon Steve Bannon, and why do you want a white supremacist as one of your advisers? Come on, Don, we both know you're lying. Now, stop it.'

''I think I would be in the position to give him a bit of a scolding and he would have to sit there and take it. Yeah, I would like an hour with Donald Trump; an hour and a half.''

And the outspoken star also claimed the president has a ''mental disorder''.

Discussing the merits of social media, he said: ''The idea of Twitter: Trumpy -- my son, Harry, and I call him 'Trumpy' -- has really got something with it.

''Rather than a laughable expression of ego run amok, it could be a useful tool.

''If we get a president sometime soon who does not have a mental disorder, Twitter will be useful.''