Sen. Rand Paul (R–Ky.) pressed Secretary of State Mike Pompeo on Thursday to say whether the Trump administration believes it has the power to go to war in Iran without congressional approval. Pompeo would not give a straight answer.

The exchange, which occurred while Pompeo was testifying before the Senate Foreign Relations Committee, came two days after President Donald Trump announced he was designating the Islamic Revolutionary Guard Corps (IRGC), a powerful Iranian paramilitary organization, as a foreign terror group. The IRGC has long faced accusations of sponsoring global acts of terror, and it's also been known to support various militant groups in the Middle East.

Paul was concerned that the White House might use the new designation to go to war with Iran without congressional authorization. The 2001 Authorization for Use of Military Force gives the president the power to take military action against any entity he believes to have been responsible for the 9/11 terror attacks.

"Do you believe that the 2001 authorization to go war with those who attacked us on 9/11 applies to Iran or Iran's Revolutionary Guard?" Paul asked Pompeo.

"I'd prefer to just leave that to lawyers," the secretary of state responded.

But Paul wasn't satisfied. "Well, I would think it would be a pretty important question that whether or not you think you have the right invade or declare war or engage in war with Iran," Paul said. Referencing the IRGC being labelled a terror group, he added: "Do you think that that somehow includes them in the 2001 [AUMF] and is that any part of the decision-making process with including this designation?"

Pompeo claimed the designation "was not part of the decision-making process. The designation was a simple recognition of reality." But Pompeo did point out that Iran has connections to al-Qaida, who carried out the 9/11 attacks.

"I am troubled that the administration can't unequivocally say that you haven't been given power. I can tell you explicitly you have not been given power or authority by Congress to have war with Iran," Paul responded. "And in any kind of semblance of a sane world, you would have to come back and ask us before you go into Iran."

This is not the first time Paul has expressed concerns over a potential war with Iran. In October, he cosponsored a bill that would largely ban money from being used for military action in Iran unless it's "in response to an imminent threat to the United States." The legislation has yet to make any progress in the Senate.

The Constitution gives Congress the authority to authorize military intervention, and in the case of Iran, it has not.

"You do not have the permission of Congress to go to war in Iran. If you want a war in Iran, you have to come to us. It's the way the Constitution was written, and it needs to be very clear," Paul said Wednesday. He said it again, just in case Pompeo missed it the first time: "You do not have our permission to go to war in Iran."

Paul is absolutely right. Hopefully, Pompeo and his boss will listen.