House Speaker Nancy Pelosi called Joint Chiefs Chairman Army Gen. Mark Milley Friday morning to discuss what she described as necessary precautions to prevent an “unhinged” president from accessing nuclear codes.

But experts and officials said there’s no place in the system for the military — or Congress — to intervene in a sitting president’s access to the nuclear arsenal.

The situation of this unhinged president could not be more dangerous, and we must do everything that we can to protect the American people from his unbalanced assault on our country and our democracy,” Pelosi, a California Democrat, said Friday in a circulated letter.

She and dozens of other lawmakers — mostly Democrats — have called for President Donald Trump’s removal from office following Wednesday’s violent takeover of the U.S. Capitol by the commander in chief’s supporters.

Milley’s office confirmed that the call took place.

“Speaker Pelosi initiated a call with the Chairman,” said Army Col. Dave Butler, Milley’s spokesman. “He answered her questions regarding the process of nuclear command authority.”

Pelosi said Friday that Trump should not be allowed to initiate “military hostilities or [access] the launch codes [to order] a nuclear strike.”

CNN reported that, after her call with Milley, Pelosi told her caucus she received assurances about safeguards should Trump decide to launch a nuclear weapon. It’s unclear what those assurances would have been since, as the Congressional Research Service wrote last month, “The President does not need the concurrence of either his military advisors or the U.S. Congress to order the launch of nuclear weapons.

“In addition, neither the military nor Congress can overrule these orders,” a December report titled “Defense Primer: Command and Control of Nuclear Forces” states.

Ankit Panda, a senior fellow with the Carnegie Endowment for International Peace’s nuclear policy program, also noted that, short of removing Trump from office, there’s no legal remedy that Milley or Pelosi can take to prevent the president from issuing a valid and legal order to use nuclear weapons.

“It’s how we designed the system,” he wrote Friday. “We could change it, of course. … If there’s a way in which the American presidency is effectively monarchical and absolute, it’s this one.”

Officials with U.S. Strategic Command, or STRATCOM, which oversees nuclear weapons, referred questions from Military.com about Pelosi’s call to Milley back to the Pentagon.

Adm. Charles “Chas” Richard, the head of STRATCOM, told reporters this week that he would not recommend changes to the system the U.S. has had in place for decades.

He would, however, decline to follow illegal orders to deploy a nuclear weapon, Richard added.

“I will follow any legal order that I’m given — I will not follow any illegal orders,” he said. “And if you go much further, if I were to say anything else, we’re starting to call in civilian control of the military, which I think is a prized American attribute.”

Ultimately, he said, who has the authority to carry out a nuclear strike is “a political question.”

“I’m prepared to execute whatever the political leadership of this nation would like to do,” he said.

In the event of preparing for a nuclear strike, the president consults with military and civilian advisers. Advisers have the ability to push back on an order they believe does not meet stipulations outlined under the laws of armed conflict, or LOAC, according to the Congressional Research Service.

During a Senate hearing in 2017, Robert Kehler, a retired Air Force general who previously served as the commander of STRATCOM, testified before lawmakers that military members can refuse what they deem to be an “illegal” order, but added, “Only the president of the United States can order the employment of U.S. nuclear weapons.”

Kehler pointed out that the process is not automatic. “This is a system controlled by human beings,” he said, according to a report from CNN. The process “includes assessment, review and consultation between the president and key civilian and military leaders, followed by transmission and implementation of any presidential decision by the forces themselves.”

Aside from nuclear weapon authorities, Milley’s role as chairman of the Joint Chiefs also, by law, falls outside of the chain of command. The role of the chairman is to serve as the president’s top military adviser.

Several experts on civilian-military relations also noted Friday that if Pelosi and other politicians are concerned about Trump posing a security risk, they should find a political solution — not a military one.

Pelosi and other lawmakers have said they will move ahead with impeachment proceedings if the vice president and Cabinet members do not invoke the 25th Amendment to remove the president from office.

 Richard Sisk contributed to this report.

— Gina Harkins can be reached at gina.harkins@military.com. Follow her on Twitter @ginaaharkins.