Sen. Mike Lee (R-Utah) agreed to co-sponsor Sen. Bernie Sanders’s (I-Vt.) bill that would prevent funding from the Pentagon to be used for military force in Iran without congressional approval, according to CNN.

“As United States senators, we often disagree on many issues. But standing up for the Constitution is not about partisanship,” the two lawmakers said in a statement to CNN.

“The Founding Fathers were absolutely clear. They wanted to ensure that our country avoided needless conflict and they understood that presidential war-making would be harmful to our democracy,” they added.

Sanders, a top-tier Democratic presidential candidate, introduced the bill following the Trump administration’s classified briefing on the U.S. decision to kill Iranian Gen. Qassem Soleimani in a drone strike last week, as well as Iran’s rocket attacks Tuesday targeting U.S. bases in Iraq.

According to the Pentagon, Soleimani was actively planning more attacks throughout the region with the explicit intention of harming U.S. service members and diplomats. After the missiles attacks in Iraq, Iran’s Supreme Leader Ayatollah Ali Khamenei said that it was “a slap in the face” to the United States and warned “it’s not sufficient.”

However, Lee said White House officials delivered the “worst military briefing” he had ever seen on Capitol Hill.

“What I found so distressing about that briefing was that one of the messages we received from the briefers was do not debate, do not discuss the issue of the appropriateness of further military intervention against Iran. And that if you do, you’ll be emboldening Iran,” Lee said.

“The implication being that we would somehow be making America less safe by having a debate or a discussion about the appropriateness of further military involvement against the government of Iran,” he continued. “I find it insulting and demeaning.”

Lee clarified that his criticism did not extend to the White House’s Iran policy in general. 

“I support President Trump. I support the way that he has wielded his powers as commander in chief. I think he’s actually been the most respectful of all presidents during my lifetime of the commander-in-chief power,” Lee said. “I think the people who briefed the Senate today did him a grave disservice.”

The House voted on Thursday in a favor of a symbolic war powers resolution directing the administration to halt the use of military force against Iran unless it obtains approval from Congress.