John Hyten
John HytenReuters

The top U.S. nuclear commander said Saturday he would push back against President Donald Trump if he ordered a nuclear launch the general believed to be "illegal".

Air Force Gen. John Hyten, commander of the U.S. Strategic Command (STRATCOM), spoke at the Halifax International Security Forum in Halifax, Nova Scotia, Canada, and was quoted by CBS News.

Hyten said he has given a lot of thought to what he would say if a president ordered a strike he considered unlawful.

"I think some people think we're stupid," Hyten said in response to a question about such a scenario. "We're not stupid people. We think about these things a lot. When you have this responsibility, how do you not think about it?"

He was responding to a question about testimony by former STRATCOM commander retired Gen. Robert Kehler before the Senate Foreign Relations Committee earlier in the week. Kehler said that nuclear operators would refuse to implement an unlawful order. Hyten agreed, and argued that the process in place to launch a nuclear strike would prevent such a situation from arising in the first place. As head of STRATCOM, Hyten is responsible for overseeing the U.S. nuclear arsenal.

"I provide advice to the president, he will tell me what to do," Hyten added. "And if it's illegal, guess what's going to happen? I'm going to say, 'Mr. President, that's illegal.' And guess what he's going to do? He's going to say, 'What would be legal?' And we'll come up with options, with a mix of capabilities to respond to whatever the situation is, and that's the way it works. It's not that complicated."

"If you execute an unlawful order, you will go to jail. You could go to jail for the rest of your life," he added, according to CBS News.

Hyten's comments come amid continued tension with North Korea. The isolated country sparked global alarm by conducting a sixth nuclear test and test-launching missiles capable of reaching the U.S. mainland.

Visiting Seoul last week, Trump warned North Korea he was prepared to use the full range of U.S. military power to stop any attack, but also urged Pyongyang to “make a deal.”

On Wednesday, Trump said that the "twisted dictatorship" in North Korea cannot blackmail the world, adding that the goal is to "denuclearize" North Korea and stressing the U.S. has made clear "all options remain on the table."

Trump had previously pledged to unleash "fire and fury" down on the North if it threatens the United States or its allies.

Hyten's comments also come as Congress is re-examining the authorization of the use of military force and power to launch a nuclear strike.

Hyten said the U.S. military is always ready to respond to the threat of North Korea.

"And we are ready every minute of every day to respond to any event that comes out of North Korea. That's the element of deterrence that has to be clear, and it is clear," Hyten said, but also opined that handling North Korea and its unpredictable leader Kim Jong Un has to be an international effort.

"President Trump by himself can't change the behavior of Kim Jong Un," Hyten said. "But President Trump can create the conditions that the international community can reach out in different ways where we can work with the Republic of Korea, where we can work with our neighbors in the region."