A former nuclear launch officer has let loose a stinging volley of tweets at Donald Trump after reports that the Republican presidential candidate asked a foreign policy expert why the U.S. can't launch nuclear weapons.

John Noonan, who once had a finger on one of the crucial buttons for the 90th Missile Wing at the F.E. Warren Air Force Base in Wyoming, unleashed 20 devastating messages on Twitter Wednesday.

They came as a reponse to the report from MSNBC's Joe Scarborough - citing an unnamed source - that Trump repeatedly asked why the U.S. can't use nukes.

"Several months ago, a foreign policy expert on the international level went to advise Donald Trump," Scarborough said. "And three times [Trump] asked about the use of nuclear weapons. Three times he asked at one point if we had them why can't we use them."

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Noonan, who is also a writer for the Weekly Standard, said in the tweets that Trump would be "undoing six decades of proven deterrence theory" and making "the single greatest strategic shift in U.S. national security in decades."

"What really concerns me," he continued, "is the idea of a narcissist walking around with nuclear authenticators.

"Imagine having to turn launch keys not knowing if we were under attack or if it was because [a] foreign leader said a mean thing on Twitter. The power is there to kill millions. Permanently alter the geopolitical landscape. It is a sacred, sobering responsibility."

Noonan pulled no punches in the 20-tweet rant, also declaring: "Nuclear deterrence is about balance. Trump is an elephant jumping up and down on one side of the scale."

Here's his full, worrying, assessment.

1. I cant get this in one tweet. So bear with me as I air some laundry here on Scarborough's claim Trump's interested in nuclear First Use

— John Noonan (@noonanjo) August 3, 2016

2. Pulled 300 nuclear alerts, 100 ft under the Wyoming turf. Job is serious and full of serious people.

— John Noonan (@noonanjo) August 3, 2016

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