Ever since Harry Truman ordered the atomic bombing of Hiroshima during World War II, the president of the United States has controlled the most lethal arsenal in history — a major reason the position is considered the most powerful on Earth.
In recent months, remarks by President Trump threatening North Korea with "fire and fury like the world has never seen" have raised new questions about the concentration of power in one person, though Trump has not explicitly said he might use nuclear weapons.
Legislation sponsored by Rep. Ted Lieu (D-Torrance) and Sen. Edward J. Markey (D-Mass) would prevent Trump or any future president from ordering a first strike with nuclear weapons without a declaration of war by Congress. The bill would maintain the president's authority to use nuclear weapons at a moment's notice if an enemy launches its weapons first.
A restriction put on the president's control of the arsenal — the 450 Minuteman land-based missiles and the roughly 1,000 warheads aboard U.S. submarines — could upend half a century of nuclear deterrence and war fighting theory. In a crisis, it would eliminate an adversary's fear of a surprise attack by the U.S.
The legislation faces little chance of passage in the Republican-controlled Congress. Still, Trump's heated rhetoric has taken past concerns about the judgment of presidents to a new level.
"It is a problem not only with this president, but all presidents," said former Defense Secretary William Perry. "This president just accentuates the problem. His personality and behavior has brought it to a fore."
In hindsight, some have questioned whether President Kennedy's judgment was compromised by painkillers for his back problems during the Cuban missile crisis. And in his final days in office, President Nixon was morose and sometimes drunk, exhibiting odd behavior. Some believe that Ronald Reagan was showing symptoms of mild dementia in his final days in office.
But the concerns about Trump are more basic.
"It is not just a concern that the president is drunk or has a brain malfunction, but that he just doesn't have the character," said Hans Kristensen, a nuclear arms expert at the Federation of American Scientists. "That is a whole different ballgame."
This perception has raised concerns that Trump might impulsively launch a preemptive nuclear attack on North Korea that would not only kill innocent civilians but also put South Korea, Japan and even the U.S. at risk of a counterattack.
Lieu, an attorney and a colonel in the Air Force reserve, argues that such an order would violate international laws of war, which require proportionality so that civilian deaths are not excessive compared with the military advantage gained. And he asserts it would violate the U.S. Constitution, because a nuclear attack would be the most extreme act of war and only Congress has the power to declare war.
Lieu questions whether senior military leaders would comply with such an order, given the legal doubts about it.
But independent military law experts worry about the legislation, and say they have no doubts that a presidential order for an attack on North Korea would be legal and executed by senior military leaders along with their subordinates.
"I would worry about destabilizing our entire nuclear strategy of deterrence," said Rachel VanLandingham, a former Air Force attorney and law professor at Southwestern Law School. "We have been very careful not to overly limit ourselves. Part of deterrence is not taking nuclear weapons off the table."
If Trump's opponents believe he is not fit to control the nuclear arsenal, she said, then the proper action is to remove him from office, not undermine the nation's nuclear deterrent, she said.
Throughout the Cold War and in the quarter-century since, the U.S. has never renounced the first use of nuclear weapons.
It threatened to use tactical nuclear weapons against Soviet Union forces if they attempted to overrun Western Europe; and it has indicated it could use them in response to biological or chemical attacks on the U.S. or its allies, said John Pike, executive director of GlobalSecurity.org, a Washington-based military analysis firm.
In the early 1950s, the U.S. had more brutal policies than today, backed by a war plan that would inflict "massive retaliation" with nuclear weapons against an enemy attack on the U.S. or its allies.
In the heat of the Cold War, President Eisenhower said the U.S. would use tactical nuclear weapons in a potential battle with communists "just exactly as you would use a bullet or anything else."
The nation's nuclear war fighting plan is shrouded in secrecy, and much of it is based on precedent. Many senior experts, including former defense officials and nuclear weapons experts, say it is not even clear what law, executive order or military regulation gives the president sole authority over nuclear weapons use.
But nobody doubts that only the president can authorize their use, Perry said.
U.S. policy has always warned adversaries that the president is ready to launch its missiles within minutes of detecting a nuclear attack against the nation, a scenario that would give the president about 10 minutes to consider the options before enemy missiles hit.
Jeffrey Lewis, a nuclear weapons analyst with the James Martin Center for Nonproliferation Studies in Monterey, Calif., said that putting nuclear missiles on alert and believing that complex decisions can be made by any president in minutes has always been unrealistic. The current controversy involving Trump has created a long overdue public discussion, he said.
"It is a crazy policy, because it is designed in complete ignorance of human beings," he said.
The nation's "launch on warning" scenario could also include a preemptive strike if the U.S. obtained intelligence that an adversary was preparing to launch its missiles, but had not yet done so.
A lot of this policy would have to be junked if the president had to ask permission to use nuclear warheads from Congress. And that's just fine with some retired four-star generals, defense secretaries, arms control experts and Lieu, the sponsor of the legislation.
Geoffrey Corn, a law professor at the South Texas College of Law in Houston and a former military attorney, said he has no doubts that senior military officers would obey an order to attack North Korea.
Unless an order were so bizarre, such as an ad hoc nuclear strike on London or Paris, the military is trained and sworn to uphold its duty to obey the president, Corn said.
"When the secretary of Defense conveys the order to the military, it comes with the assumption that it has been legally vetted," Corn said. "I can't imagine that an officer would legally refuse to execute an order for a preplanned attack."
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