Updated at 10:15 a.m. ET Thursday

There was some consternation Monday on Capitol Hill after President Trump told the United Nations General Assembly that "if [the U.S.] is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea." Congress is, after all, the only branch of government constitutionally authorized to declare war. And that would seem to include nuclear war.

But Senate Foreign Relations Committee Chairman Bob Corker says it's complicated.

"Every president since we've had nuclear weapons has had the ability to launch them," Corker noted. "That's the way our nation is."

Asked in a brief interview at the Capitol about legislation that would give Congress a greater say over the decision to carry out a first strike, Corker replied, "I've had other members talk with me a little about it, and we're doing some research on that topic." He added, "We really began to do so at the end of last week."

NPR previously reported that Corker was referring to a bill sponsored by one of his committee members, Massachusetts Democrat Ed Markey. Titled "Restricting First Use of Nuclear Weapons Act of 2017," it explicitly forbids the first use of nuclear weapons without authorization from Congress through a declaration of war.

Corker's office subsequently notified NPR that there had been a "miscommunication" in the interview. The Tennessee Republican, according to his staff, was speaking more broadly about the constitutional question of when Congress needs to intervene when the nation goes to war.

Markey, for his part, says the bill he introduced four days after Trump's inauguration (an identical bill, H.R.669, was introduced the same day in the House by California Democrat Ted Lieu) is more relevant than ever. "The more the president talks about the total destruction of North Korea," he says, "the more it's necessary for the country and the Congress to have a debate over what the authority of a president is to launch nuclear weapons against another country."

The push to place a legislative check on Trump's power to unleash a nuclear strike faces significant obstacles. Congress has long been averse to declaring war — it has not done so since the U.S. entered World War II in 1941. And a bill requiring a nuclear war declaration would very likely face a presidential veto.

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