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.
Against the backdrop of these headlines is the steady erosion of arms control agreements that trace back to the Cold War. The centerpiece of this framework is known as the Strategic Arms Reduction Treaty, or START, which when signed in 1991 reversed an arms race between the US and the Soviet Union, mandating the reduction of nuclear arsenals together with inspection and verification in both countries.
START was agreed to shortly before the fall of the Soviet Union but was later expanded in a 2010 agreement between the United States and Russia to further reduce arsenals and maintain verification in both countries. This deal, known as New START, was extended for five years — through February 2026 — in the early months of Biden’s presidency.
Then came the Ukraine war, after which Russia suspended its participation in the treaty and blocked American inspectors from its nuclear facilities. Hopes of renewing the treaty or negotiating further extensions have remained dormant ever since.
While Russia claims to still be complying with its obligations, the treaty expires altogether in three months, and there are no signs of work to negotiate a new accord. The demise of START would remove the last remaining arms control treaty between the world’s leading nuclear powers. Trump’s aversion to international agreements and perceived unfairness in such accords toward US interests makes new arrangements further unlikely.
So, while the risk of a nuclear exchange may remain low, the world is entering an era not seen since the Cold War, with a potential free-for-all expansion of nuclear weapons by the two leading nuclear powers (accounting for 90% of all deployable weapons systems), as well as by countries not yet in the nuclear club.
South Korea, faced with a nuclear armed adversary to the north and questions over American security guarantees, has debated the merits of acquiring its own nuclear capability. Saudi Arabia has long warned that it will obtain a nuclear weapon absent American security guarantees in the event Iran ever does the same and recently signed a mutual defense pact with Pakistan, a nuclear armed power.
Extending the US nuclear deterrence umbrella to Saudi Arabia may be a topic when the Saudi crown prince visits Washington later this month for meetings with Trump.
While nuclear arms control agreements like START curbed the expansion of American and Russian nuclear arsenals, there has never been such an agreement in place for China. Given Beijing’s adversarial positioning, Trump has a fair point in making clear that the US will keep pace and remain ahead of both Russia and China.
China’s nuclear arsenal is growing by approximately 100 new warheads per year, faster than any other country. According to the Bulletin of the Atomic Scientists, Beijing now possesses 600 nuclear weapons, together with advanced missile delivery systems that can strike the US. These experts predict that China may possess 1,500 nuclear weapons by 2035, with strike capabilities from land, sea, and air (known as a full nuclear triad).
While the country is a recognized nuclear power under the Nuclear Non-Proliferation Treaty, or NPT, it has never engaged in serious arms control talks to curtail its buildup.
Beijing argues its nuclear stockpile pales in comparison to the US or Russia (each with over 5,000 warheads) and thus it should not be treated similarly as it goes about a rapid nuclear expansion. This argument cuts against the spirit of nuclear non-proliferation that undergirds the NPT system. It also calls the entire system of strategic stability that START established further into doubt, heralding an expansion of nuclear arsenals and nuclear-armed powers, together with heightening risk of mistrust and miscalculation.
Even at best, therefore, the world is entering an uncharted era of expanding nuclear arsenals without any of the traditional guardrails that have existed for decades.
Now, add the entry of artificial intelligence into decision-making and military analysis, and the world may also be moving perilously closer to a once-fictional “Doomsday Machine” scenario from Stanley Kubrick’s “Dr. Strangelove” (1964). That machine contained an automatic nuclear launch program outside human control under certain conditions, an absurdity created by humans to ensure their own destruction without human input.
This is no longer fictional.
Only last year, when Biden met Chinese leader Xi Jinping, the two “affirmed the need to maintain human control over the decision to use nuclear weapons,” according to the White House readout of the meeting. This principle for humans and not AI to control nuclear use in all circumstances might seem obvious, but it’s not backed by any treaty or formal agreement.
Even if human judgment controls a decision at launch, machine judgments are being integrated into analysis cycles, compressing timeframes in a crisis, with risks of miscalculations driven by AI modeling as opposed to human judgment.
While the risk should not be overstated, Ukraine remains the current flashpoint.
Trump’s order last week to renew nuclear tests came in response to Putin’s provocatively overseeing nuclear exercises, including the launch of missiles capable of carrying nuclear warheads and reaching the US. Moscow claimed the exercises were routine, but the timing and saber-rattling came after Trump poured cold water on a rumored second summit with Putin, as well as Russia’s failure to gain new ground on the battlefield in Ukraine.
This is not the first time that Putin has brandished a nuclear threat over his flailing military campaign in Ukraine. In February 2024, Putin warned that “NATO nations assisting Ukraine … genuinely poses a risk of a conflict involving nuclear arms, which would lead to the annihilation of civilization.” This past summer, Russia’s former president and deputy chair of its security council, Dmitry Medvedev, warned Trump on continuing US support for Ukraine and pointed to Russia’s nuclear strike capacity. In response, Trump ordered the deployment of submarines carrying nuclear weapons toward Russia.
Trump has been right to call Moscow’s rhetorical bluff, while keeping diplomatic channels open toward a ceasefire together with support for Ukraine. However, the exchange of words together with exercises and deployments should heighten the concern about any further proliferation of nuclear weapons in a polarized environment.
Essential: Deterrence and diplomacy
All the above demonstrates that there is something to the recent headlines on nuclear weapons and popular movies about a loose nuke poised to annihilate Chicago. The risks of a nuclear exchange are small but increasing. Earlier this year, what is known as the “Doomsday Clock,” a predictor of nuclear catastrophe set by the Bulletin of the Atomic Scientists, was moved to the closest point since its inception in 1947.
So, Trump is right to clearly identify this most serious problem, and to make clear that the US will not sit idle as its adversaries expand their own nuclear capabilities. Investments in our own systems must ensure a deterrent to any thought of using a nuclear weapon by anyone and under any circumstance. Congress earlier this year mandated an increase in spending to modernize and maintain our nuclear arsenal considering China’s advances and tensions with Russia. That’s right to do. Maintaining nuclear deterrence has served the world and the US well for over 75 years and must continue.
Washington might also consider extending its nuclear deterrence umbrella to countries not within our web of mutual defense treaties, such as Saudi Arabia and the Gulf states. Such a move together with ensuring a country like Iran never obtains a weapon reduces risks of proliferation, as the American umbrella renders further expansion of new nuclear powers unnecessary. At the same time, Washington can coordinate with partners around the world on new restrictions, particularly on the use of AI in command systems, and calling on Beijing to curb its own rapid and unnecessary expansion of nuclear warheads.
New explosive tests would not help this equation. Moscow carried out its last test in 1990. Washington in 1992. Beijing in 1996. The moment the U.S. conducts an explosive test, Russia and China would surely do the same, removing another brick from the non-proliferation system. Nor are new tests needed to maintain readiness and modernization of the US nuclear arsenal. This is one nuclear genie to keep locked in the bottle.
Trump’s nominee to oversee US Strategic Command, which is responsible for the global command and control of nuclear weapons, seems to agree. In questioning before the Senate Armed Services Committee about Trump’s apparent order to renew nuclear tests on an “equal basis” with China and Russia, Vice Adm. Richard Correll answered, “Neither China nor Russia has conducted a nuclear explosive test. So, I’m not reading anything into that or reading anything out.” Trump should drop this idea.
Note: In breaking news, Secretary of Energy Chris Wright late Sunday further walked back Trump’s apparent order, saying any tests would be standard “systems tests,” and “not nuclear explosions.” But Trump, in an interview with 60 Minutes aired after Wright but recorded earlier, suggested China and Russia are carrying out secret nuclear tests, requiring the US to do the same.
While there is no reported indication of China or Russia secretly exploding nuclear bombs, Trump could ask the Senate to ratify the Comprehensive Nuclear Test Ban Treaty (CTBT) if both China and Russia do the same. The CTBT has sat dormant in the Senate since the late 1990s. Russia was a signatory but withdrew in 2023. China like the US was a signatory but never ratified the accord.
This would be a better approach, perhaps even worthy of a Nobel Prize, than renewing explosive tests.
The world is entering an unmapped era of nuclear risk. The answer is not new explosive tests, but a coordinated campaign with allies and partners to maximize deterrence against any conceivable use, while working to establish new norms against further expansion of nuclear weapons and managing the use of AI in decision-making systems. A new era of risk demands new arrangements and standards, which as of now, are nowhere in sight.