Count James Clapper among those who disdained President Donald Trump's rally in Phoenix, the tone of which has the former director of national intelligence questioning the president's fitness, motives and access to nuclear codes.

"It's just so objectionable on so many levels," Clapper said on CNN late Tuesday night after the president's rally. "I don't know when I've listened and watched something like this from a president that I found more disturbing."

"This behavior, this divisiveness, this complete intellectual, moral and ethical void that the president of the United States exhibits, and how much longer does the country have to, to borrow a phrase, endure this nightmare," said Clapper, now a national security analyst for CNN. "Having some understanding of the levers of power that are available to a president, if he chooses to exercise them, I found this downright scary and disturbing."

And with one of those levers being the nuclear codes, Clapper said Trump could be a threat to national security.

"I worry about, frankly, the access to nuclear codes. In a fit of pique, he decides to do something about Kim Jong Un? There's actually very little to stop him," Clapper told CNN's Don Lemon. "The whole system's built to ensure rapid response, if necessary, so there are very little in the way of controls over exercising a nuclear option, which is pretty damn scary."

Clapper said Trump "should have quit while he was ahead" after Monday night's measured — and teleprompter-driven — speech outlining his vision and strategy for Afghanistan.

Instead, Clapper is now in the camp of questioning Trump's fitness to be president, and motives for the tone of his Phoenix remarks.

"I really question his ability, his fitness to be in this office. I'm also beginning to wonder about his motivation . . . maybe he is looking for a way out," Clapper said.

Clapper said he found some solace from Republican Sen. Bob Corker, who last week strongly rebuked Trump in the wake of his vacillating remarks about Charlottesville.

"I'm hopeful that other similarly thoughtful Republicans will reach the point where enough is enough," Clapper said.