For those of us who weren’t around for the Cold War, here’s a quick primer. Following our joint efforts to defeat the axis powers in WWII, the capitalist, liberal-democratic United States and the communist, authoritarian Soviet Union proceeded to lock horns for almost half a century in a drawn-out struggle for global hegemony. As they engaged in a slow, tense game of geopolitical chess the two superpowers both amassed absurdly huge nuclear arsenals, each easily capable of destroying humanity several times over. At our peak in 1967, the U.S. had a stockpile of just over 31,000 nuclear warheads – now we’re down to 6,970. In 1988 the Soviet Union possessed a peak stockpile of 45,000 warheads and Russia currently has the most in the world with 7,300.

Despite the unparalleled military might possessed by both the U.S. and the Soviet Union, the two sides never actually fired a shot at each other (with the exception of some proxy wars in China, Korea, Africa, and the Middle East). Many attribute the lack of conflict in this standoff to a theory called MAD, an acronym which stands for Mutually Assured Destruction. The idea is straightforward enough - if two hostile actors are both capable of destroying each other instantaneously and the defender will inevitably launch a counterstrike against the attacker, neither side has any incentive to initiate a conflict as it would only cause their own destruction. If the U.S. nukes the Soviets, the Soviets nuke the U.S. and important as our reasons for hating each other may have seemed in the moment they’ll inevitably seem petty in light of a nuclear winter and mass human extinction.

The acronym MAD seems fitting, as the arrangement appeared utterly mad to many of the civilians involved. For example, my dad used to tell me about the drills he remembers his school rehearsing to prepare for the eventuality of war. He said all of the kids would have to get on the ground under their desks, not unlike the earthquake drills that California students are accustomed to practicing. It was always a bit of an exercise in futility though, a good bit of security theater, as some drywall and a wooden desk seem unlikely to shield a vulnerable child from the nuclear bomb the Soviets would have presumably dropped on Los Angeles. This looming sense of existential dread was far from normalized, and in 1982 one of the largest political demonstrations in U.S. history saw a million protestors take to Central Park to call for an end to the Cold War arms race.

As a result of disarmament policies and the collapse of the Soviet Union in 1991, recent decades have seen the world shed many of its nuclear weapons instead of producing more. Nevertheless, the same dynamic remains in which Russia and the U.S. each have more nuclear warheads than all of the other countries with nukes combined – albeit on a smaller scale. Diplomatic relations between the two countries have been terse, though mostly successful overall. However, recent years have seen tensions rise as the U.S. hit Russia with devastating economic sanctions in response to their annexation of Crimea in 2014. The man at the center of these developments is former KGB agent Vladimir Putin, who served his first term as Russian President from 2000-2008, then was Prime Minister for four years, and was elected President again in 2012 following the extension of term limits. On Thursday, Putin met with some of his military advisors and stated that Russia needs to enhance the capability of its nuclear arsenal – a vague statement which was quickly met with a tweet by U.S. President-elect Donald Trump.

Trump tweeted that “The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes”, a statement which hints at the potential upending of disarmament and non-proliferation policies. This apparently comes soon after he met with incoming military officials at his Mar-a-Lago resort, where one topic of discussion was modernizing the U.S. nuclear arsenal. While modernizing doesn’t necessarily mean producing more warheads, the call for “expansion” would seem to mean an increase in quantity, not just quality of weapons. Putin responded at his annual press-conference Friday by saying that Trump’s remarks didn’t surprise him, as they mirrored many made by the Republican candidate on the campaign trail. He also made sure to mention that Russia’s “advanced” ability to overcome missile defense systems is more efficient than U.S. missile defense.

President-elect Trump responded by calling in to MSNBC’s Mika Brzezinski Friday morning and saying “Let it be an arms race. We will outmatch them at every pass and outlast them all.” This bold statement sent aides scrambling to explain and seems to eliminate any doubts about Trump’s desire to reverse U.S. nuclear policies, while begging countless questions – particularly whether the soon-to-be 45^th President of the United States understands the gravity of what he could be about to step into. Regardless, the future of a conflict with the power to end life as we know it now rests in the hands of a reality star turned President and a former Soviet spy who wants to restore his country’s former 'greatness'. Maybe we should all get under our desks, just to be safe.