President Trump considers questions casting doubt on his mental fitness to serve as commander in chief “disgraceful and laughable,” the White House said Thursday.

“If he was unfit, he probably wouldn’t be sitting there,” White House press secretary Sarah Huckabee Sanders said at her daily briefing.

“This is an incredibly strong and good leader,” Sanders said of the president.

Questions about the president’s mental health are being asked more openly in response to excerpts from a forthcoming book about the Trump White House.