The former chief strategist for Mitt Romney's 2012 presidential campaign blasted President Donald Trump during a Tuesday appearance on MSNBC's "All In."
Stuart Stevens, a member of The Lincoln Project, is author of the new book It Was All a Lie: How the Republican Party Became Donald Trump.
Host Chris Hayes played a clip of Trump's interview with Axios White House correspondent Jonathan Swan.
"I'm curious what your thinking was watching that interview," Hayes said.
"It's still just unbelievable that this man is president of the United States," Stevens replied. "He's a guy that really you wouldn't want to sit next to on a long plane flight. Just across the board, he's an idiot."
"This is why people are always trying to give Trump this idea well, you know, he's doing this and it's fourth-dimensional chess or fifth-dimensional chess or tenth-dimensional chess because otherwise, you have to come to grips with the fact that he's a blithering idiot. But he's a blithering idiot," he explained. "He can't even carry on a conversation about current events which, God forbid, he is at the center of those events."
"I don't see how as an American -- forget Republican, Democrat, whatever -- how if you really care about America, you can honestly say the country is in good hands with this person as president of the United States. It's inconceivable," he declared.
Hayes asked if current Republican strategists have the same view of Trump.
"Stupidity is not contagious. The ability to ignore stupidity is contagious and that's what's happened here," he replied. "All of these people that I've worked with, they are appalled by Donald Trump, they're frightened by Donald Trump."
"It's appalling. It's a fundamental patriotic test and a fundamental moral test that the Republican Party is failing," Stevens added.
Watch: