1954's Castle Bravo test

1954's Castle Bravo test United States Department of Energy

America’s Allies Are Becoming a Nuclear-Proliferation Threat

Some of the United States' oldest allies are considering the once-unthinkable: building their own nuclear weapons.

As the Trump administration scrambles traditional foreign-policy practice, experts warn that some of America’s longest allies are increasingly considering what would previously have been unthinkable: the pursuit of nuclear weapons.

Days after the 2016 American election, Reuters published an interview with Roderich Kiesewetter, foreign policy spokesperson for German Chancellor Angela Merkel’s conservative bloc. Reacting to President Trump’s victory, Kiesewetter declared, “Europe needs to think about developing its own nuclear deterrent.”

It was shocking. Germany’s flirtations with nuclear weapons have been minimal since it committed to nonproliferation in the 1960s. But prominent academics and journalists joined Kiesewetter. The publisher of one influential conservative newspaper even suggested that Germany develop its own nuclear arsenal.

“We initially thought this was going to go away because of how vociferous the opposition was; that it was a phantom debate among fringe elements,” said Tristan Volpe, fellow at the Carnegie Endowment for International Peace’s nuclear program. “But it’s come back at least four times with some serious people weighing in as proponents.” 

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Germany is not unique. Of all the Trump administration’s global impacts, one of the most worrying is a sudden increase in the risk of nuclear proliferation among American allies, many of whom are considering a nuclear path which America may be unable to control.

This debate has been most intense in South Korea, which began pursuing a nuclear weapons program in the 1970s only to abandon it under intense pressure. The idea remained popular; upwards of 60 percent of South Koreans favor pursuing nuclear weapons.

“South Korea has become much more serious,” said David Santoro, nuclear policy director at Pacific Forum, a Honolulu thinktank. “A number of politicians have been making the case that South Korea should develop a nuclear arsenal.” Former South Korean foreign minister Song Min-soon told an American audience last year that “the Republic of Korea taking its own measures to create a nuclear balance on the peninsula” was “widely touted.”

The most significant steps by an American partner are being taken by Saudi Arabia. It is pursuing civil nuclear capabilities and, according to Carnegie’s Volpe, “have been quite reluctant to foreswear the option to enrich uranium down the road. They’ve been very coy around it. Well, working-level officials in Saudi Arabia have been very coy.” That reticence does not extend to Saudi leaders. Crown Prince Mohammed bin Salman warned in 2018 that if Iran “developed a nuclear bomb, we will follow suit as soon as possible.”

‘Trump’s instincts and style’

These shifts are partly the product of long-term trends. Never since the Cold War has America’s global position seemed more fragile, making its commitments seem questionable. And North Korea’s success in acquiring long-range nuclear capabilities was guaranteed to spook nearby American allies. As Mira Rapp-Hooper, Senior Fellow for Asia Studies at the Council on Foreign Relations, has observed, “The trouble is, the United States has far less incentive to intervene on behalf of South Korea or Japan if North Korea can respond with a nuclear strike against the U.S. homeland.” Iran’s interest in nuclear weapons has similarly terrified regional rivals.

But Trump’s behavior has accelerated those trends. Santoro noted that the nuclear discussion in South Korea is “taking off now because there’s a lot of discussions in Washington about whether or not the Trump administration is considering withdrawing troops.” Vipin Narang, associate professor of political science at MIT, said, “You can really boil this down to Trump’s instincts and style. For the first time in a long time, the allies have had to fundamentally question the credibility of the U.S. [nuclear protection] guarantee.”

This uncertainty is fed by moves like Trump’s demand, since rescinded, that South Korea quintuple its contribution to the cost of maintaining American troops there. “The concern is that it’s not a genuine negotiating position, that it’s demanded as an excuse to eventually pull out of South Korea,” Narang said. “There’s a deep enough thread in Trump’s thinking and rhetoric to suggest that he genuinely believes that American [nuclear] assurance and conventional deployments to these allies are a waste of money.”

Opening the box

Experts emphasize that the risk of allies rapidly nuclearizing is low. “There’s a number of hurdles that [allies] would have to get very powerfully motivated to overcome,” said Michael Mazarr, senior political scientist at the RAND Corporation. But Volpe observed that “opening that box and having to ask those questions about the U.S. commitment is worrisome…The proliferation risk is low. The problem is that it’s increased. It was an almost 0 percent risk for a long time, and the reason there’s lots of interest is that that risk has gone up in a noticeable way.”

Moreover, that risk will grow. According to Nicholas Miller, assistant professor of government at Dartmouth: “There are geopolitical trends that are making this happen, and are going to make it increasingly common…The shift towards multipolarity with the rise of China, the relative decline of the U.S, and Russia behaving increasingly assertively—that all makes a lot of our allies feel more insecure. That’s going to persist, so these conversations will continue.”

Part of the Trump administration’s legacy will be the corrosion of America’s ability to control those risks. Previous administrations restrained proliferation by denying other governments access to technology, coercing them through threats, and reassuring them through commitments. But the rise of Russian and Chinese nuclear-technology providers has made the first option far less effective. And it would be counterproductive to coerce already-nervous allies with the type of confrontational strategies used against states like Iran and North Korea.

The only useful tool the next president will have is reassurance, itself badly dulled by the current president. “From an allied perspective, you look at the U.S. and you think, ‘Well, for four years I’ll get assurance, but then the administration will change and the commitment might die again’,” Santoro said. “It’s going to be very hard for the next administration to recommit to U.S. obligations.”

The consequences of proliferation among allies are dire. Miller explained that “the more countries with nuclear weapons, the more likely that a weapon gets used. That could be a deliberate attack, accident or nuclear terrorism.” Crucially, “the U.S. has adopted a strong stance against proliferation [because] we’re very worried about cascades or tipping points. If one [ally] gets nuclear weapons, it gives others incentives to do the same”.

As the 2020 election looms, this issue will grow in importance. “I think most allies are willing to give American until 2020, but if Trump is reelected, then I think these concerns will be really exacerbated,” said Narang. “Because that’s enough time for Trump to implement a vision of reducing America’s footprint.”

So as America negotiates its way through the Trump question, the answer it chooses may require it to confront a newly pressing nuclear challenge: holding back its own friends.