Brett McGurk is a CNN global affairs analyst who served in senior national security positions under Presidents George W. Bush, Barack Obama, Donald Trump and Joe Biden.

In the summer of 2022, I accompanied President Joe Biden to a summit in Saudi Arabia with leaders from across the Middle East. During a working session, someone asked Biden to name one issue that kept him up at night.

Without flinching, Biden said nuclear war.

I was surprised by the answer, because the threat-of-all-threats had seemed contained over the recent decades. But at the time, with Europe on the front end of a war launched by Russia, a nuclear-armed power, the erosion of nuclear arms control arrangements, together with the rise of artificial intelligence and a burgeoning nuclear arms race with China, it’s a surprise the issue had not received more attention given the stakes.

Biden later told CNN’s Jake Tapper that Russian miscalculations in Ukraine “could all end in Armageddon,” though he said the risks remained low at the time.

Fast forward to this past week. The most-watched movie on Netflix is “A House of Dynamite,” about a nuclear missile heading for Chicago and evading air defenses. Russian President Vladimir Putin oversaw nuclear exercises, including a new missile system that can strike anywhere on Earth. In response, President Donald Trump ordered “immediate” renewal of nuclear weapons tests after a three-decade moratorium. Russia threatened to do the same.

What is going on? Let’s try to make sense of things.

US President George H.W. Bush, left, and his Soviet counterpart, Mikhail Gorbachev, confer during a joint news conference on July 31, 1991, in Moscow concluding a US-Soviet summit dedicated to disarmament. Mike Fisher/AFP/Getty Images

Loosening restrictions

Against the backdrop of these headlines is the steady erosion of arms control agreements that trace back to the Cold War.