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The panel warned against legislative changes to rein in the President's authority to exercise nuclear authority

Republican members did seek assurance that there are legal and strategic oversight measures in place

Washington CNN  — 

Congressional lawmakers raised concerns about President Donald Trump’s ability to use nuclear weapons during a hearing Capitol Hill Tuesday amid bipartisan anxiety over launch process procedures and indications that the administration has considered the option of a first strike on North Korea.

Members of the Senate foreign affairs committee called into question a decades-old presidential authority to deploy nuclear weapons in what was the first congressional hearing on nuclear authorization in decades.

“We are concerned that the President of the United States is so unstable, is so volatile, has a decision-making process that is so quixotic that he might order a nuclear weapons strike that is wildly out of step with US national security interests,” said Sen. Chris Murphy, D-Connecticut.

Sen. Ed Markey, a Democrat from Massachusetts, echoed those concerns: “Many Americans fear that the President’s words could turn into nuclear reality.”

Republican members of the committee were less blunt in their criticism of Trump’s judgment but did seek assurance that there are legal and strategic oversight measures in place to prevent the rash use of nuclear weapons.

Ultimately, the panel warned against legislative changes to rein in the President’s authority to exercise nuclear authority.

“I think hard cases make bad law, and I think if we were to change the decision-making process in some way because of a distrust of this President, I think that would be an unfortunate precedent,” said Brian Mckeon, who previously served as Principal Deputy Under Secretary of Defense for Policy during the Obama administration.

Retired Air Force Gen. Robert Kehler, who previously served as the commander of US Strategic Command under President Barack Obama, explained that there are layers of safeguards within the current system designed to ensure any order is both legal and proportionally appropriate.

“US nuclear forces operate under strict civilian control. Only the President of the United States can order the employment of US nuclear weapons,” Kehler said at the hearing.

“This is a system controlled by human beings … nothing happens automatically,” he said, adding that the US military does not blindly follow orders and a presidential order to employ nuclear weapons must be legal.

While the President retains constitutional authority to order some military action, Kehler explained that the nuclear decision 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.”

(FILES) A picture taken in 1971 shows a nuclear explosion in Mururoa atoll. France said on March 24, 2009 it will compensate 150,000 victims of nuclear testing carried out in the 1960s in French Polynesia and Algeria, after decades of denying its responsibility. An initial sum of 10 million euros (14 million dollars) has been set aside for military and civilian staff as well as local populations who fell ill from radiation exposure, Defence Minister Herve Morin told Le Figaro newspaper. AFP PHOTO FILES / STRINGER (Photo credit should read -/AFP/Getty Images)
How fast can a nuke fly? (2016)
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“If there is an illegal order presented to the military, the military is obligated to refuse to follow it,” he said.

Dr. Peter Feaver, a professor of public policy and political science at Duke University, also highlighted the point that any nuclear launch would be preceded by a review and consultation process.

“The system is not a button that the President can accidentally lean on against the desk and immediately cause missiles to fly as some people in the public, I think, fear it would be,” Feaver testified, adding that the decision requires the President to work with military aides who are attending him – who have possession of the materials he needs – and personnel at all levels from top commanders all the way down to service members working in the missile silo to carry out an order.

“The President by himself cannot press a button and cause missiles to fly. He can only give an authenticated order which others would follow and then missiles would fly,” he said.

The administration has been trying to soothe concerns by arguing the existing launch process that presidents have operated under for decades has sufficient checks in place that would discourage Trump from taking imprudent action. Trump himself has had multiple briefings on the nuclear launch cycle and more conventional, non-nuclear alternatives.

CNN’s Barbara Starr and Jim Acosta contributed to this report