Trump says he's 'like, really smart ... a very stable genius'

President Donald Trump wants people to know he's "like, really smart'' and "a very stable genius.''

He's taking to Twitter to defend his mental fitness and boast about his intelligence.

It's his latest pushback against a book that portrays him as a leader who doesn't understand the weight of the presidency. In the book, former aide Steve Bannon questions Trump's competence.

Trump's having none of it.

He says critics are "taking out the old Ronald Reagan playbook and screaming mental stability and intelligence.''

Trump says "my two greatest assets have been mental stability and being, like, really smart.''