In the waning days of Richard Nixon’s administration, when he had sunken into depression and heavy drinking, his secretary of defense told Pentagon officials to check with him before executing any nuclear launch order from the distraught president.

Four decades later, the story suggesting a check on nuclear strikes may seem like comfort for those worried that President Trump may impulsively decide to back up an angry tweet with an atomic warhead. However, in a new podcast, the author of a new book on the nuclear launch system tells International Business Times that there is nothing preventing Trump from suddenly initiating an attack for any reason and that the current missile system was deliberately designed to begin launching a nuclear weapon instantly after a president issues an order.

“The goal of the entire system is that from the moment a president gives the launch order, four minutes later the first U.S. intercontinental ballistic missiles leave their silos,” Garrett Graff, author of “Raven Rock: The Story of the U.S. Government’s Secret Plan to Save Itself -- While the Rest of Us Die,” told IBT. “This Nixon story stands out because it is the only time in the history of the United States and nuclear weapons where a president has had any limitation to their nuclear launch authority.”

Podcast subscribers can click here to hear the full podcast discussion with Graff.

President Trump’s supposedly improvised statement that he would respond with “fire and fury” to any North Korean threats have left experts and much of the general public concerned about the prospect of impending nuclear war, led by a head of state with a reputation for acting first and thinking later. Many have openly expressed hope that there might be some type of safeguard in place so that Trump isn’t the sole decision-maker authorizing a nuclear launch. The bad news for them: He is.

“This is the most concerning nuclear situation that we have faced perhaps ever in the history of the U.S. presidency, in part because we see threats that are more real today than we have seen in decades,” said Graff.

In fact, the president’s order is the only point in the entire nuclear launch system that does not require the approval of a second person. On nuclear submarines and in missile silos, two officers must both approve the launch of nuclear weapons. The president, however, must only consult with two senior military officials. But the final decision remains solely and squarely with the president; he does not need the approval of those officials. In fact, the entire nuclear launch system was designed specifically so that there are as few impediments as possible between the president and the ability to launch nuclear weapons.

“This is a system that was designed for the peak of the Cold War, to reflect a reality that we no longer face in the United States,” said Graff. “We designed this system to respond on a hair trigger to an attack of tens of thousands of weapons. That is both not the strategic reality that we face with Russia an more, nor is it the most likely geopolitical scenario that we would face with North Korea.”

The military aide with the so-called “nuclear football” that lets the president start a nuclear war was photographed with a guest at Trump’s Mar-a-Lago resort in February. However, the binder does not actually hold a big red button, but is rather a series of binders with predetermined types of nuclear war and missile targets that the president selects from.

“The binder actually has a visual guide in the front of it,” said Graff. “One military aide referred to it as the ‘Denny’s menu of nuclear war.’ You just point at these pictures and that would be the nuclear war that you would order up.”

A bill introduced in both chambers of Congress in January by Democrats Sen. Ed Markey of Massachusetts and Rep. Ted Lieu of California would curb the president’s first strike authority. The bill would make it so that the president cannot launch nuclear weapons unless an enemy has first launched nuclear weapons at the U.S., or Congress has declared a war specifically authorizing a nuclear strike. However, the bill has been sitting in committee since January.

“It is a frightening reality that the U.S. now has a commander in chief who has demonstrated ignorance of the nuclear triad, stated his desire to be ‘unpredictable’ with nuclear weapons, and as President-elect was making sweeping statements about U.S. nuclear policy over Twitter,” Lieu said in a statement when he introduced the bill.

With the bill languishing in committee, others have taken heart in the Constitution’s 25th Amendment, which holds that if the president is unable to fulfil his duties as president he may be removed by the vice president and senior White House officials. In theory, the 25th Amendment could be cited by top administration officials if they believed a nuclear launch order reflected a president whose mental state made him unable to fulfill his duties. However, the process for initiating proceedings to remove the president based on the 25th Amendment would likely take weeks. By the time Vice President Pence penned a letter invoking the 25th Amendment to remove Trump from office -- should he even choose to do so -- nuclear missiles could already be in the air.

The Cold War-era system is intended to work this way. While it might seem reassuring that other high-level officials, like White House Chief of Staff John Kelly or Defense Secretary Jim Mattis, might have put in checks on presidential powers in the same fashion as James Schlesinger, the defense secretary in the Nixon administration, there is no evidence that they have actually done so. If they have made checks against Trump, it would be counter to what the system was designed to do.

“That would be a direct contradiction to the way our system is supposed to work,” said Graff. “The president is supposed to have entirely unilateral nuclear launch authority.”