Trump’s Virus Treatment Revives Questions About Unchecked Nuclear Authority

President Trump’s long rants and seemingly erratic behavior last week — which some doctors believe might have been fueled by his use of dexamethasone, a steroid, to treat Covid-19 — renewed a long-simmering debate among national security experts about whether it is time to retire one of the early inventions of the Cold War: the unchecked authority of the president to launch nuclear weapons.

Mr. Trump has publicly threatened the use of those weapons only once in his presidency, during his first collision with North Korea in 2017. But it was his decision not to invoke the 25th Amendment and turn control over to Vice President Mike Pence last week that has prompted concern inside and outside the government.

Among those who have long argued for the need to rethink presidents’ “sole authority” powers are former Defense Secretary William J. Perry, considered the dean of American nuclear strategists, who has cited the fragility of a nuclear-weapons control chain and the fear that it can be subject to errors of judgment or failure to ask the right questions under the pressure of a warning of an incoming attack.

Mr. Trump’s critics have long questioned whether his unpredictable statements and contradictions pose a nuclear danger. But the concerns raised last week were somewhat different: whether a president taking mood-altering drugs could determine whether a nuclear alert was a false alarm.

That question is a new one. The military’s Strategic Command often conducts drills that simulate actual but inconclusive evidence that the United States may be under nuclear attack. Such simulations drive home the reality that even a president asking all the right questions could make a mistake. But they rarely simulate what would happen if the president’s judgment was impaired.

“A nuclear crisis can happen at any time,” Tom Z. Collina, the policy director at the Ploughshares Fund, a private group that seeks to defuse nuclear threats, noted last week in an opinion piece. “If such a crisis takes place when a president’s thinking is compromised for any reason,” he added, “the results could be catastrophic.”

Traditionally, presidents have temporarily conveyed authority — including nuclear launch authority — to the vice president when they anticipated being under anesthesia. Ronald Reagan took that step in 1985, and George W. Bush did so in 2002 and 2007. There was no indication that Mr. Trump was unconscious, but there was reason to be concerned that the cocktail of drugs he was given could impair his judgment to make the most critical decisions entrusted to a president.

Last week in telephone interviews with Fox News and Fox Business Network, Mr. Trump said he was no longer taking experimental medications but was still on dexamethasone, which doctors say can produce euphoria, bursts of energy and even a sense of invulnerability. On Friday, he told Fox News he was off the drug, which he appears to have taken for less than a week.

But during that week, his prolific Twitter activity and rambling interviews led many to question whether the drugs had accentuated his erratic tendencies. His doctors’ refusal to describe with any specificity his condition or treatment only played up the concern.

“The history of obfuscating the medical condition of presidents is as old as the Republic,” said Vipin Narang, a professor at the Massachusetts Institute of Technology who has studied the nuclear command-and-control chain. “The issue here is that the dex” — shorthand for dexamethasone — “can make you paranoid and delusional.”

“We don’t know how much he was given,” Mr. Narang said. “And if he gives an order in the middle of the night, and no one is there to stop him, we are dependent on his military aide not to transmit the order or the duty officer at the national military command center to stop it.”

The military’s standard response is that it would carry out a “legal order” after authenticating that it truly came from the president. But that narrow answer does not address the problem that no other senior officials — the secretary of defense, the chairman of the Joint Chiefs of Staff or the commander of Strategic Command, which has responsibility for the nuclear arsenal — are required to sign off.

Government officials refuse to say whether they were taking any special precautions when Mr. Trump was taking the drugs. In conversations over the past week, which they would not hold on the record, several pointed to the stories surrounding Richard M. Nixon’s last days in office in 1974. He was drinking heavily and talking to portraits on the walls, and his aides feared he was emotionally unstable.

His secretary of defense, James R. Schlesinger, a hawkish cold warrior, said he instructed the military not to react to White House orders on nuclear arms unless they were cleared by him or Secretary of State Henry A. Kissinger. (Mr. Schlesinger died in 2014, and Mr. Kissinger, now 97, has said that he had no knowledge of such an arrangement.)

If Mr. Schlesinger’s account is true, it was “certainly extralegal,” Mr. Narang said. There is no evidence that anyone around Mr. Trump, including Mr. Pence or Defense Secretary Mark T. Esper, whom Mr. Trump has reportedly frozen out of key decisions, had any enhanced authority while the president was on medication.

The “sole authority” tradition is unusual among the world’s nine nuclear powers; even Russia requires two out of three designated officials to sign off on a nuclear launch. While the Constitution says that only Congress can declare war, the speed of bombers and missiles made clear during the Cold War that there would be no time to convene Congress or mount a defense. As a result, Congress began delegating to the president all powers to use nuclear weapons during Harry S. Truman’s administration. He is the only president who has ordered a nuclear strike.

Officials from many nations felt the immense pressure surrounding such a decision during a simulation of a launch exercise conducted this year at the Munich Security Conference, the leading gathering of the West’s national security officials. Volunteers donned virtual reality headsets and were put through the head-spinning flow of data that comes in as a president faces a 15-minute window to decide whether to launch ground-based missiles before they are destroyed.

There were tiny hints throughout that suggested there could be a false alarm, but the evidence was muddy.

“The last finger I would want on the nuclear button,” said Hans M. Kristensen, the director of the Nuclear Information Project at the Federation of American Scientists, a private group in Washington, “is that of a president on drugs.”

It is not a new problem: John F. Kennedy took powerful pain medications, though there is no evidence that his judgment was impaired during the Cuban Missile Crisis, the closest the United States and the Soviet Union came to a nuclear exchange.

But no one understands exactly how the drugs given to Mr. Trump interact. And according to scientists, the most common mood enhancements associated with dexamethasone are mania and hypomania, a euphoric state. The hallmarks of hypomania include inflated self-esteem, increased talkativeness, decreased need for sleep, racing thoughts, distractibility and absence of restraint to engage in activities that could invite personal harm.

Not surprisingly, the military imposes strict limitations on the officers who oversee the nation’s nuclear forces. Known as the Personnel Reliability Program, it assures that the authority is vested in people “who demonstrate the highest levels of integrity and dependability” and whose behavior is observed “on a frequent and consistent basis.” A 1991 study said thousands of nuclear personnel were decertified every year.

Peter D. Zimmerman, a physicist and former government arms scientist, said few things better illustrated the confused nature of the American effort to prevent a single individual from launching a nuclear strike than the “two-man rule” in nuclear silos, submarines, bombers and the nation’s coast-to-coast atomic complex.

The rule requires the presence of two authorized people for any step involving access to the armaments or the launching of a nuclear strike. “No unaccompanied person ever approaches a nuclear weapon,” Dr. Zimmerman wrote in a 2017 opinion essay. “It’s a basic precaution against theft, misuse or sabotage.”

But it does not apply to the commander in chief, whether in the Oval Office or at Walter Reed National Military Medical Center.

A president could misjudge the situation or become impulsive, Dr. Zimmerman noted in an interview. “And the consequences,” he said, “would be horrendous.”