If President-elect Donald J. Trump meant what he said, then the world may one day look back to recall that the first superpower nuclear arms race since the Cold War was announced by two pajama-clad talk show hosts.
“Let it be an arms race. We will outmatch them at every pass and outlast them all,” Mika Brzezinski, of MSNBC’s “Morning Joe” program, said on Friday. She and her co-host, curled up in holiday-themed nightwear in front of a fake fireplace, said the quote was a statement from Mr. Trump, elaborating on a Twitter message on nuclear weapons.
Mr. Trump has a history of bluster and his declarations may turn out to be bluffs. But should he follow through on instigating a nuclear arms race, the consequences could be severe. Best estimates of likely Russian and Chinese responses offer a concerning guide. So do lessons from the Cold War arms race, which brought the world so close to the brink that once-hostile American and Soviet adversaries worked to reverse the competition they had once seen as essential.
What is the aim of an arms race?
Nuclear arms races are not usually something that states set out to provoke, but are pulled into against their wills.
In the Cold War, the United States and the Soviet Union saw themselves as reacting to one another, straining to maintain a strategic balance that would deter war or at least make it survivable.
Winston Churchill remarked in 1954 that more warheads could accomplish little more than to “make the rubble bounce.”
But this quote reflects a long-held misunderstanding: that the arms race was a simple matter of accruing warheads.
In fact, it was far more dangerous, with ever-growing stockpiles merely reflecting complex tit-for-tat advances. For instance, one country might develop weapons that could deliver warheads more rapidly, which would require the other to shorten its response time and build redundant, retaliatory weapons.
While “arms race” describes the sets of policies that helped make the Cold War so dangerous, arms racing was not in itself policy. Rather, it was a much-lamented — and much-feared — byproduct of American and Soviet aims. Leaders on both sides wanted to avoid losing, but none saw the race as desirable.
The exception, Ronald Reagan, entered office in 1981 determined to win the Cold War in part by outstripping the Soviet Union on nuclear arms. But after a few years of tightening response times and near-miss incidents, he became the most enthusiastic proponent of nuclear disarmament to occupy the Oval Office.
Though some Americans believe the arms race won the Cold War, as Mr. Reagan had initially hoped, the two sides ended their competition willingly — and a few years before internal political and economic forces would pull down the Soviet Union from within.
Mr. Reagan and the Soviet leader, Mikhail Gorbachev, sought total disarmament at a 1986 summit meeting. Unable to agree on terms, they settled for an ongoing drawdown of nuclear forces, reversing the arms race.
Such reductions have continued since, codified in treaties such as the 2010 New Start agreement, which Mr. Trump’s policy would likely undo.
In his Twitter post on Thursday announcing that policy, Mr. Trump said his goal was that “the world comes to its senses regarding nukes.”
It is not clear what that means. But whatever his intention, analysts say that Mr. Trump’s stated desire to provoke an arms race does have a foreseeable range of outcomes.
Russia: Trading safety for parity
The two countries most likely to respond are Russia, whose nuclear arsenal is comparable to that of the United States, and China, which has a far smaller program.
Though each has a slightly different goal, both design their programs to counterbalance the United States, and will therefore calibrate to keep pace with any American advances.
But analysts warn that, in part because the United States is already so much more powerful in conventional terms, Russia and China may feel forced to take actions that are destabilizing and put all parties at risk.
Since the end of the Cold War, Moscow has seen nuclear parity with the United States as its last — perhaps only — guarantee of survival against a far stronger Western alliance it perceives as an existential threat. Falling behind would, in Moscow’s view, invite Russia’s destruction.
Though Russia’s economy is a fraction the size of America’s, it has kept up. Should it find parity too costly, Moscow would likely compensate by expending another kind of currency: its willingness to accept nuclear risk.
This would be aimed at strengthening Russian deterrence against any American threat. For instance, Russia might deploy more nuclear-capable Iskander missiles to Kaliningrad, a Russian enclave located between Poland and Lithuania. Such missiles can reach European capitals in a matter of minutes and, because they are fired from special vehicles, can be difficult to knock out.
Vladimir V. Putin, the Russian president, could also loosen restrictions on the use of nuclear weapons. Some analysts already believe that Russian military doctrine allows for the use of a single “de-escalatory” nuclear strike, in case of a conventional war, to force the other side to stand down. Such policies put a greater onus on the United States to reduce risk, compensating for any relative Russian weakness.
China: ‘It’s a scary new world’
Beijing’s nuclear aims are less ambitious: to retain just enough ability that, should the United States attack first, it can fire a few nuclear weapons in retaliation.
Should Mr. Trump advance American nuclear abilities — even if this is aimed principally at Russia — China will fear that an American first strike could wipe out its warheads. This would render China’s nuclear deterrent effectively obsolete, all but forcing it to compensate.
Vipin Narang, a nuclear weapons expert at the Massachusetts Institute of Technology, said China would build up its own abilities, but worried that it would seek a quicker fix as well.
China might preload nuclear warheads onto missiles to shorten its response time, Mr. Narang suggested. Or it could hide missiles in hardened locations, like tunnels. It might consider adopting Pakistan’s practice of putting warheads in unmarked vans and driving them around the country, in a never-ending road trip, to keep them safe from attack.
China could also decide to abandon its policy against the first use of nuclear weapons in any conflict “because they could not afford to go second,” Mr. Narang said.
Mr. Narang emphasized that such steps would increase the risk of an accident or miscalculation that, while remote, could be catastrophic.
Of Mr. Trump’s intentions and their likely impact in Beijing and Moscow, Mr. Narang said, “It’s a scary new world if he’s serious about, and trying to trigger, an arms race with either or both.”
A game with no victory
Paul C. Warnke, a senior Pentagon official in the Cold War’s early years, concluded that their mutual buildups were less like a race than two runners on adjacent treadmills. “The only victory the arms race has to offer,” he wrote in 1975, was to “be first off the treadmill.”
Mr. Warnke’s view was controversial at the time, but later became accepted even by many dedicated Cold Warriors. The early 1980s had seen near misses that had brought the world intolerably close to the edge.
In 1983, for instance, a Soviet early-warning system detected an incoming American nuclear attack. It happened to be a moment of high tension in which the Kremlin had feared a pre-emptive strike.
Because of missile advances that had come as part of the arms race, the Soviets had only 23 minutes to respond before the missiles would land — not enough time to double-check equipment, much less negotiate with Washington. The arms race also dictated that the Soviet Union respond with overwhelming retaliation against the United States, to quickly neutralize any further threat.
The Soviet officer in charge of the early-warning station could see no evidence of a false alarm, but told his superiors that it was. His guess, proved correct, may have saved the world.
Though the episode would not become public for years, Mr. Reagan wrote in his memoirs that another war scare, which occurred that same month when Soviet forces shot down a South Korean airliner that had wandered into Soviet airspace, “demonstrated how close the world had come to the precipice and how much we needed nuclear arms control.”
Mr. Reagan principally turned against the arms race because of its dangers, but others came to oppose it for the simple reason that, after decades and billions or perhaps trillions of dollars, it had failed to accomplish victory.
“Building nukes to get others to stop historically has had the same effect as telling everyone in an email storm to cease using ‘Reply All,’ ” Joshua H. Pollack, an expert at the James Martin Center for Nonproliferation Studies, joked on Twitter.
Mr. Pollack added, “There is no last, winning move when it comes to arms racing.”
The first response came from Cheryl Rofer, a retired nuclear scientist at the Los Alamos National Research Laboratory: “But there is a last move.”