HALIFAX, Canada — The head of U.S. Strategic Command on Saturday said he would refuse to execute an order from President Donald Trump to launch a nuclear weapon if he believed its use was illegal.

Gen. John Hyten, who oversees the operation of nuclear weapons, told participants at the Halifax International Security Forum that he and Trump have already had discussions about the nuclear decision-making process. Hyten would likely be the final person that Trump would talk to, should the president decide to move forward with a nuclear strike.

“I think some people think we’re stupid. But we’re not stupid people. We think about these things a lot,” Hyten said.

“The way the process works is simple. I provide advice to the president, he’ll tell me what to do, and if it’s illegal, guess what’s going to happen?” he said. “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 of a mix of capabilities to respond to whatever the situation is.”

One of the biggest questions raised by Hyten’s fellow panelists was how the United States — and Trump specifically — should respond to North Korea’s escalating nuclear test and development activities. However, there were no easy answers.

Hyten spoke about North Korea’s most recent missile launch in September, which he and U.S. Defense Secretary Jim Mattis watched together at STRATCOM headquarters in Offutt Air Force Base, Nebraska. According to Hyten, the launch showcased the U.S. military’s situational awareness of the North’s nuclear activities, as he and Mattis were able to see the North Korean missile take off from Pyongyang, fly over Japan and land in the Pacific Ocean.

That level of insight, coupled with the United States’ nuclear arsenal, plays a deterrent role, Hyten said.

“The president’s direction to me is to create the conditions for diplomacy to work by being ready all the time, 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,” he said. “If he goes down that path, it will not end well, but my goal is to create the room for diplomacy and sanctions to work.”

Other experts sitting in on the panel, however, said more needs to be done on a diplomatic level to tighten sanctions on North Korea.

Sung-han Kim, director of Ilmin International Relations Institute of Korean University, said the international community needs to bring North Korea back to the negotiating table through “maximum pressure.”

“Quite frankly, for the past 25 years, we didn’t have a chance to implement real sanctions, but after North Korea conducted the sixth nuclear test, I think we came up with a package of real sanctions even though it is not quite sufficient,” he said.

Bonnie Jenkins, a former ambassador and the U.S. State Department’s coordinator for threat reduction programs, agreed with Sung-han about the need for tougher sanctions, calling them the “only thing that we have available.”

Moshe Ya’alon, the former Israeli minister of defense, characterized North Korea as an “irrational player,” while the United States has adopted a tactic of “irrational words” in response. Trump’s fiery words toward North Korea are not always a bad thing, he argued.

“The silence, on behalf of North Korea is a result of fear. If you are [going up against] an irrational player, you should demonstrate irrationality: ’Yes, I’m ready to go all the way to deter you,’ ” he said.