According to an anecdote shared by MSNBC's Joe Scarborough Wednesday morning, Donald Trump once repeatedly questioned why the United States "can't use nuclear weapons."

In an interview with former CIA director Michael Hayden, Scarborough recounted the conversation between Trump and a “foreign policy expert on the international level” that allegedly took place several months ago.

“Three times he asked about the use of nuclear weapons," the "Morning Joe" host said of Trump. "At one point, ‘If we have them, why can’t we use them? Three times in an hour briefing, ‘Why can’t we use nuclear weapons?’”

Scarborough's remarks spurred more than a few aghast reactions, but none more scathing or comprehensive than a tweetstorm unleashed by John Noonan, who advised former Gov. Jeb Bush (R-Florida) and Gov. Mitt Romney (R-Massachusetts) on national security.

Noonan was also a nuclear weapons launch officer in the U.S. Air-Force.

Cliff / Flickr - flickr.com

Speaking from experience, Noonan stressed that the decision to use a nuclear weapon is a serious and complicated job.

He explained the nuclear deterrence theory that has guided much of U.S. foreign policy since the Cold War.

"The deterrence concept is straight-forward," a report published by the the Brookings Institution, a nonprofit public policy organization, explains. "Persuade a potential adversary that the risks and costs of his proposed action far outweigh any gains that he might hope to achieve. To make deterrence credible, the United States built up powerful strategic, theater and tactical nuclear forces that could threaten any potential aggressor with the catastrophic risks and costs of a nuclear retaliatory strike against his homeland."

"The purpose of nukes is that they are never used," Noonan asserted, advising readers to "buckle the hell up" should Trump take office and put his loose talk about the nuclear arsenal into action.

He also referenced some of Trump's other troubling remarks on foreign policy and the NATO alliance.

But the self-described "former nuke guy" explained that what worried him most was Trump's temperament. He virtually echoed a jab from Hillary Clinton's address at the Democratic National Convention: "A man you can bait with a tweet is not a man we can trust with nuclear weapons."

Noonan explained that changing the U.S. government's stance on nuclear weapons could have catastrophic impacts around the globe.

Others pointed out that Trump had posed the same troubling question about nuclear weapons during a March MSNBC town hall event.

Trump campaign manager Paul Manafort, for his part, denied Scarborough's claims on Fox News.

[h/t Chris Garrigues]

[h/t Daily Intelligencer]