He threatened any country that interfered in his invasion of Ukraine with “consequences greater than any you have faced in history.” He placed his nuclear forces on high alert and held exercises with them. And then he proclaimed that Western sanctions amounted to a “declaration of war” against Russia.

The fate of humanity suddenly seems to be in the unsteady hands of an isolated, frustrated, and potentially unhinged Vladimir Putin. And people are understandably panicked about that prospect. “The fact that there’s a very short path from, say, Putin feeling humiliated to the end of life as we know it,” the sociologist Kieran Healy wrote, “is literally insane.”

At this point of the conflict over Ukraine, the odds are that the Russian president’s threats amount to a bluff intended to intimidate and coerce his opponents in the West. But regardless of whether the risk of nuclear war has actually increased, Putin’s actions have opened our eyes to how dependent we all are on the whims—or even the missteps or miscalculations that fallible, emotional, semi-rational human beings make when moving quickly in crisis—of one man and his nuclear arsenal.

Our current predicament should, in fact, open our eyes wider still to the more profound problem of a similar susceptibility in the United States and other nuclear-armed countries—and to how few checks there truly are on leaders who decide to use the world’s most destructive weapons.

The reactions to Putin’s threats remind me of 2017, when Donald Trump started unleashing nuclear threats against North Korea, and many Americans began to understand the U.S. president’s expansive power to use nuclear weapons. Be it with Putin now, Trump then, or a Watergate-addled Richard Nixon in the 1970s, the delicate nature of the world’s framework for deterring nuclear war typically dawns on people only when leaders of nuclear states start acting in extraordinary and seemingly reckless ways, even though the underlying condition of vulnerability is always present.

“The entire system of nuclear deterrence is and always has been incredibly dangerous and fragile,” Eryn MacDonald, a global-security analyst at the Union of Concerned Scientists, told me. “We tend not to notice this—or, perhaps, are more able to push this knowledge far enough into the background to ignore how disturbing it is—until there is a crisis that brings the absurdity of the whole system into focus.”

We don’t know a lot about how exactly the authority to launch nuclear weapons works in Russia. This opacity is deliberate. All nuclear command-and-control systems, including America’s, have a “first rule of Fight Club”-like aspect to them: You don’t talk much about them, to keep your enemies guessing. But Pavel Podvig, an expert on Russian nuclear forces (who, even armed with all his knowledge, speaks about some of his assessments in terms of guesswork), has concluded that the Russian president can probably order the use of nuclear weapons on his own, even if the country’s policies aren’t necessarily designed that way.

The Russian system, which dates back to the 1970s and was crafted with Soviet-era collective, centralized decision making in mind, calls for the defense minister and the chief of the military’s general staff to be looped in on any orders by the country’s leader to use nuclear weapons, giving them an opportunity to influence the decision. (Experts think each of these figures possesses a Cheget, Russia’s rough equivalent of the American “nuclear football,” though whether all three briefcases are needed to transmit a nuclear-launch order is unclear.) If, as some speculate he might in the course of the conflict in Ukraine, Putin were to reach for his tactical nuclear weapons—a lower-yield, shorter-range variety that can be deployed on the battlefield—he would need to remove them from storage and prepare them for use in a relatively protracted process that would ostensibly involve more consultations.