In the wake of President Donald Trump’s incitement this week of a violent mob to assault Congress to halt the certification of his election loss, longstanding advocates of taking away the presidency’s authority to carry out a pre-emptive nuclear strike see an opening for their cause.

With even some Republicans publicly stating that Trump in his final two weeks of office is mentally unwell, concerned activists and supportive lawmakers such as Rep. Ted Lieu, D-Calif., are pressing their case and calling for both immediate and longer-term steps to prevent current and future presidents from being able to order a first-strike nuclear attack.

For decades, the U.S. president has had the sole authority and complete discretion to order an initial nuclear strike on an adversary.

“With a mentally unstable president, you can’t just rely on him being his own check and balance,” Lieu said Friday, discussing the bicameral legislation he plans to reintroduce with Sen. Edward J. Markey, D-Mass., that would forbid any U.S. president from launching a pre-emptive nuclear attack without the express approval of Congress.

Speaker Nancy Pelosi also said in a Friday letter to Democratic House members that she spoke earlier in the morning to Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, about “available precautions for preventing an unstable president from initiating military hostilities or accessing the launch codes and ordering a nuclear strike.”

“All indications are that the president has become unmoored, not just from his duty, or even his oath, but from reality itself,” Rep. Adam Kinzinger, R-Ill., an Air National Guard veteran of the wars in Iraq and Afghanistan and one of the few GOP members to call for Trump’s removal by the 25th Amendment, said in a Thursday video message. “The president is unfit and the president is unwell and the president must now relinquish control of the executive branch voluntarily or involuntarily.”

While the pro-Trump extremists rioted around the Capitol complex on Wednesday, Lieu, a former Air Force attorney said he spent a good portion of the lockdown huddled with his House Foreign Affairs colleague, David Cicilline, D-R.I., drafting language for articles of impeachment against Trump as well as a letter to acting Defense Secretary Christopher Miller that implores him to provide a check in Trump’s final days in office on his ability to order a nuclear attack.

“As members of Congress who served in the military, we are writing to request that you and your combatant commanders consider ways to provide a check and balance on the President’s nuclear strike authority in the final days of his presidency,” reads the Thursday letter sent by Lieu, former Navy reservist and Afghanistan veteran Rep. Jimmy Panetta, D-Calif., and former Marine reservist Rep. Salud Carbajal, D-Calif.

The trio point to the precedent set in August 1974 during President Richard Nixon’s final days in office when he was drinking heavily and viewed as unstable by many with proximity to him.

“As President Richard Nixon prepared to leave office, then-Defense Secretary James Schlesinger issued orders requiring that military commanders check with either him or then-Secretary of State Henry Kissinger before executing any nuclear launch order by the president,” states the letter, which was obtained by CQ Roll Call. “Donald Trump is detached from reality, angry and acting out. To safeguard our country from potential catastrophe, similar steps to those taken in August 1974 need to be taken now.”

If Trump is not removed from office via the 25th Amendment or the impeachment process, Lieu acknowledges there is little else lawmakers can do in the next two weeks to wrest nuclear control from the president’s hands other than beseeching the common sense of senior Pentagon and military leaders to act with caution before carrying out any potential nuclear-related orders from Trump.

Unstable nuclear order

The nuclear chain-of-command launch authority was developed during the Cold War when speed and efficiency were prioritized amid fears the United States would have little warning to respond to a surprise attack by the Soviet Union on the homeland or on NATO allies.

Policies on atomic weapons use vary among those countries that maintain nuclear arsenals. For example, China has a longstanding stated policy of no-first-use for its nuclear arsenal. But Russia has gradually expanded the types of scenarios that it says would merit a first-use nuclear attack, including in a new military doctrine finalized last summer that gives Russian President Vladimir Putin the ability to order a nuclear attack if critical Russian military infrastructure appears to be under imminent catastrophic conventional attack.

“I now think that the Russia policy is similar or the same as the U.S. policy, which to me is terrifying,” said Tom Collina, policy director at the anti-nuclear Ploughshares Fund, noting that Russia’s military capabilities for identifying a possible missile attack haven’t been updated in years, creating a heightened risk of miscalculation in a moment of crisis.

For this reason, many anti-nuclear advocates have called on President-elect Joe Biden to issue some type of declaration early in his administration that the United States is no longer a first-use nation or that would require concurrence by additional senior officials before a nuclear attack order can be carried out.

Calls for Biden to adopt a more restrained nuclear attack policy have only grown in recent days amid alarm about Trump’s mental state and a desire to send a reassuring message to the American public and foreign allies and adversaries alike.

“[Wednesday’s] violence and governmental chaos reinforced what we already know: no one person, not even a president, should be given the sole authority to start a nuclear war, which could lead to the immediate death of millions,” Laura Grego, senior scientist in the Global Security Program at the Union of Concerned Scientists, said in a statement.

Grego said the policy should be changed to require that two other elected officials “in the line of succession” concur with a presidential order to use nuclear weapons.

The political moment for such an action by Biden is ripe, said Collina, warning that if too much time passes, people might become lulled into complacency again.

“The danger here is that President Biden comes in and, rightly so, people are reassured. I don’t think anyone is worried that President Biden is going to launch [pre-emptive] nuclear war,” Collina said. “The problem is that there may be another Trump in our future. “

Steve Andreasen, the former director for defense policy and arms control on the National Security Council during the Clinton administration, said an executive order by Biden is “the most promising path for strengthening the process by which the president will receive thorough and timely advice to inform a decision on the potential use of a nuclear weapon.” Such an executive order “could later be reinforced in legislation.”

Of course, any Biden executive order declaring a more restrained nuclear launch policy could be reversed by a successor president just as Trump unilaterally withdrew the United States from the multinational nuclear deal with Iran that the Obama administration painstakingly negotiated.

“While a future president could reverse any policies or process a president put in place, establishing them (preferably, early in a new administration) will send a strong signal of the president’s dedication to informed yet timely decision-making, and create a baseline for future presidents on this critical matter,” Andreasen, who now teaches at the University of Minnesota’s Humphrey School of Public Affairs, said in an email.

Fear that a Trump-like successor could unilaterally revert the United States back to its expansive nuclear attack posture means that Congress should take action through legislation, argued Lieu, noting strong constitutional arguments exist for permanently taking away the presidency’s pre-emptive nuclear attack authority.

Opponents such as Lieu of this unilateral power argue it goes against the intent of the Constitution, which places the power to declare war solely in Congress’ hands. Because any pre-emptive nuclear attack on a foreign country would amount to a de facto act of war, only Congress should be able to approve one, the thinking of this group goes.