WATCH: Congress must ‘keep executive in check’ with ‘unhinged’ Trump at helm, Dem Rep says

A Democratic lawmaker says President Trump’s mental health is no laughing matter, and is calling on Congress to keep the executive in check.

“I do believe that we have to watch the president, we have to make sure that we do our constitutional duty to keep the executive in check because I do think the president is, not fit for the job,” Arizona Democratic Rep. Ruben GallegoRuben GallegoOne year later: Puerto Rico battles with bureaucracy after Maria Grassley to administration: You must consult Congress on refugee cap Arizona voters like Kyl but few think he'll stick around MORE told The Hill Tuesday.

Talk of Trump’s mental stability has been front and center in recent days following the release of Michael Wolff’s book “Fire and Fury: Inside the Trump White House,” which paints a picture of White House aides who are fearful of the president’s state of mind. 

Over the weekend, however, Trump denounced the book and declared himself to be a “stable genius.” 

Asked if the president is a “stable genius,”  Rep. Dave Brat (R-Va.) said “I think he’s having fun saying that, alright?” 

Wolff’s book release coincided with reports of an unofficial Yale psychiatrist’s diagnosis of the president, adding to the talk of Trump’s mental health. Brat called the unofficial diagnosis ridiculous. 

“Ninety percent of academics are on the way left; shrinks from Yale, I mean, I could go on with stand-up lines for the next 10 minutes,” Brat, a former economics professor at a small Virginia liberal arts college, joked with The Hill. 

“People, if they want to engage in the drama aspect of politics they are more than welcome to do that, but it should probably be on an entertainment show, not the news,” Brat added.

The lawmakers’ comments come hours after Rep. Brendan Boyle (D-Penn.) announced in a press release that he plans to introduce the "Stable Genius Act" in the House on Tuesday. The legislation would require presidential candidates to undergo a mental health examination.

Watch the video above to hear the lawmakers in their own words.