It is the closest modern-day equivalent of the medieval crown and scepter—a symbol of supreme authority. Accompanying the commander in chief wherever he goes, the innocuous-looking briefcase is touted in movies and spy novels as the ultimate power accessory, a doomsday machine that could destroy the entire world.

Officially known as the “president’s emergency satchel,” the so-called nuclear “Football”—portable and hand-carried—is built around a sturdy aluminum frame, encased in black leather. A retired Football, emptied of its top-secret inner contents, is currently on display at the Smithsonian National Museum of American History. “We were looking for something that would demonstrate the incredible military power and responsibilities of the president, and we struck upon this iconic object,” says curator Harry Rubenstein.

Contrary to popular belief, the Football does not actually contain a big red button for launching a nuclear war. Its primary purpose is to confirm the president’s identity, and it allows him to communicate with the National Military Command Center in the Pentagon, which monitors worldwide nuclear threats and can order an instant response. The Football also provides the commander in chief with a simplified menu of nuclear strike options—allowing him to decide, for example, whether to destroy all of America’s enemies in one fell swoop or to limit himself to obliterating only Moscow or Pyongyang or Beijing.

Although its origins remain highly classified, the Football can be traced back to the 1962 Cuban missile crisis. Privately, John F. Kennedy believed that nuclear weapons were, as he put it, “only good for deterring.” He also felt it was “insane that two men, sitting on opposite sides of the world, should be able to decide to bring an end to civilization.” Horrified by the doctrine known as MAD (mutually assured destruction), JFK ordered locks to be placed on nuclear weapons and demanded alternatives to the “all or nothing” nuclear war plan.

A declassified Kennedy memo documents the concerns that led to the invention of the Football as a system for verifying the identity of the commander in chief. The president posed the following chilling, but commonsense, questions:

“What would I say to the Joint War Room to launch an immediate nuclear strike?”

“How would the person who received my instructions verify them?”

According to former Secretary of Defense Robert S. McNamara, the Football acquired its name from an early nuclear war plan code-named “Dropkick.” (“Dropkick” needed a “football” in order to be put into effect.) The earliest known photograph of a military aide trailing the president with the telltale black briefcase (a modified version of a standard Zero-Halliburton model) was taken on May 10, 1963, at the Kennedy family compound in Hyannis Port, Massachusetts. Since 1963, the Football has become a staple of presidential trips, and was even photographed in Red Square in May 1988, accompanying President Ronald Reagan on a state visit to the Soviet Union. (Reagan’s Soviet counterpart, Mikhail Gorbachev, was accompanied by a military aide who was clutching a very similar device, known in Russian as the chemodanchik, or “little briefcase.”)

A recurring complaint of presidents and military aides alike has been that the Football, which currently weighs around 45 pounds, contains too much documentation. President Jimmy Carter, who had qualified as a nuclear submarine commander, was aware that he would have only a few minutes to decide how to respond to a nuclear strike against the United States. Carter ordered that the war plans be drastically simplified. A former military aide to President Bill Clinton, Col. Buzz Patterson, would later describe the resulting pared-down set of choices as akin to a “Denny’s breakfast menu.” “It’s like picking one out of Column A and two out of Column B,” he told the History Channel.

The first unclassified reference to the existence of the Football is contained in a formerly top-secret memorandum from 1965 obtained by the National Security Archive of George Washington University. Tasked with reducing the weight of the Football, a senior defense official agreed this was a worthy goal, but added, “I am sure we can find strong couriers who are capable of carrying an additional pound or two of paper.”

For the Football to function as designed, the military aide must be nearby the commander in chief at all times and the president must be in possession of his authentication codes. Both elements of the system have failed on occasion. According to the former chairman of the Joint Chiefs of Staff, Gen. Hugh Shelton, Clinton mislaid his laminated code card, nicknamed the “Biscuit,” for several months in 2000. “This is a big deal, a gargantuan deal,” the general complained in his 2010 autobiography, Without Hesitation: The Odyssey of an American Warrior.

An even closer brush with disaster came during the attempted assassination of Reagan in March 1981. During the chaos that followed the shooting, the military aide was separated from the president, and did not accompany him to the George Washington University hospital. In the moments before Reagan was wheeled into the operating theater, he was stripped of his clothes and other possessions. The Biscuit was later found abandoned, unceremoniously dumped in a hospital plastic bag. It seems unlikely that a crown or scepter would have been treated so cavalierly.