Why Trump’s Retreat from US Allies Could Have Nuclear Consequences

The factors that drove South Korea to pursue nuclear weapons were quite clear: Pyongyang’s “unabated hostility toward Seoul” and the fact that “South Korean confidence in the U.S. security commitment…has declined.” That intelligence assessment was written by the CIA in 1978 about developments earlier that decade but it could easily be written today about South Korea or a number of other U.S. allies. 

Back then, America’s security partners were alarmed by the Nixon Doctrine, which conveyed to allies that they would need to provide for their own defense; U.S. troop withdrawals from the region; and Washington’s desire to mend relations with China. This environment drove South Korea and Taiwan to pursue nuclear weapons. 

Today, it is President Trump’s “America First” approach to foreign policy. His hostility to what he refers to as “so-called allies” and his embrace of the very dictators U.S. alliances are designed to defend against are leading allies and partners across the globe to wonder whether Washington can no longer be counted on. As in the past, regional threats are growing and the United States is once again planning to pull troops from allied territory. It should not come as a shock if a U.S. ally or partner were to determine today that it needed to launch, or relaunch, its own effort to develop nuclear weapons or the capability to quickly build them. 

Since the 1990s, America has become accustomed to thinking about nuclear proliferation as a problem associated with “rogue states”: Iraq, Libya, North Korea, Iran, and Syria. But throughout much of the nuclear age, U.S. allies, partners, and non-aligned countries were of greatest proliferation concern. West Germany, South Korea, Japan, Taiwan, Australia, Sweden, Egypt, Brazil, and others explored or pursued nuclear weapons—and India, Pakistan, and Israel acquired them.

One of the reasons Washington made extensive security commitments throughout the world—including by offering the protection of its nuclear umbrella—is so that countries would not feel compelled to develop their own nuclear weapons. Critically, that requires those countries to believe the United States would come to their defense if attacked. But as our recent report on proliferation dangers highlights, confidence in U.S. reliability is eroding. Over the past three and a half years Trump’s actions have put that alliance system at risk, fomenting some of the very same doubts and insecurities among U.S. partners that led allies to consider nuclear weapons in the past. 

Trump has repeatedly cast doubt on whether the United States would honor its security commitments. He has implied that whether Washington comes to the defense of its allies would depend on whether they have paid their “dues” into the alliance—a not-so-subtle attempt to strong-arm allies to increase their defense expenditures and compensate the U.S. for costs associated with U.S. bases. Trump said he could “go either way” on keeping U.S. troops in South Korea and Japan—where such U.S. commitments have helped deter U.S. adversaries and prevent proliferation for decades. Adding insult to injury, he reportedly mocked the accents of South Korean President Moon and former Japanese Prime Minister Abe to a crowd of donors, while bragging that Moon had “caved” to Trump in negotiations over cost sharing. It’s hard to see how these allies would believe that, when the chips are down, Trump would come to their defense today. 

Trump has talked approvingly of Russian leader Vladimir Putin, and pushed to bring Russia back into the G7 over the objection of other members. Although his administration has recently taken a tougher tact against China, Trump tweeted amidst protests in Hong Kong in August 2019 that President Xi was a “great leader who very much has the respect of his people,” and that he is in a ‘tough business.’ And he has repeatedly praised the intellect and governing prowess of North Korean dictator Kim Jong Un. It is hard to see how allies would believe that Trump takes their interests in to account, and historically such fears of abandonment have been an important motivating factor for nuclear weapons. Indeed, this fear of U.S. abandonment was key to West Germany’s exploration of nuclear weapons in the 1950s and 1960s. The potential for U.S. troop withdrawal and growing Soviet threats led then Chancellor Adenauer to conclude that “NATO is finished” and that Germany could not afford to “remain a nuclear protectorate” of the United States. 

Some dismiss President Trump’s rhetoric as cheap talk, but unfortunately these views have manifested in administration policy. Trump’s sudden announcement following his first meeting with Kim Jong-Un that the United States and South Korea would suspend joint military exercises (which Trump referred to as “war games,” using the North Korean terminology, and which he later went on to dismiss as a waste of U.S. money) shocked South Korean officials, who were not consulted beforehand. The initial U.S. demand that Seoul triple the amount it pays as part of the cost-sharing arrangement for U.S. bases on the peninsula (known as the Special Measures Agreement) has caused South Koreans to wonder whether the President was trying to break up the alliance. Finally, the U.S. has announced plans to withdraw one-third of U.S. troops from Germany—no doubt a decision taken in part because of Trump’s dispute with German Chancellor Angela Merkel—and is reviewing U.S. troop levels in South Korea as well. It should therefore come as no shock if an allied head of state uttered the same words allegedly used by then South Korean President Park before creating the organization that would lead South Korea’s covert nuclear and missile program: “We need to free ourselves from being jerked around by America’s policy positions.”

To make matters worse, Trump has implied that the United States won’t impose any penalties on allies for deciding to go nuclear. His mostly-forgotten comments during the campaign that he would be okay with Japan, South Korea, and Saudi Arabia having nuclear weapons have new resonance given his clear desire to pull U.S. troops back and allow countries to fend for themselves. For example, administration officials have tended to downplay and excuse concerns over potential Saudi nuclear and missile activity. When questioned whether the U.S. had any objections to Saudi threats to produce nuclear weapons, the White House Press Secretary punted, saying that she was not aware of any U.S. policy on that matter. In doing so, the administration is sending a message to allies that nonproliferation doesn’t matter, especially for allies willing to spend billions on U.S. defense equipment. Here again, history would suggest that how the U.S. treats one allied proliferator can be a motive for another: South Korea’s President Park believed that Washington would come to accept South Korea’s weapons program, just as it had Israel’s. 

So far no country is openly dashing for the bomb, but allies appear to be hedging their bets. There has been an uptick in the debate in South Korea over whether to develop nuclear weapons. Germany appears increasingly willing to consider a European alternative to the U.S.-provided nuclear umbrella. Saudi Arabia is improving its nuclear capabilities and keeping its options open to enrich and reprocess. Officials in countries from Turkey to Brazil have spoken approvingly of developing nuclear weapons. A number of countries—including Saudi Arabia, Turkey, Japan, Australia and South Korea are improving or plan to improve their domestic missile or space programs, thereby providing pathways to potential nuclear weapons delivery options. For some of these countries, the development of these capabilities is tied to concerns about U.S. staying power. 

It is hard to imagine that the U.S. alliance system—and Washington’s nonproliferation track record—could survive another four years of a Trump presidency. By comparison, a Biden administration would bring a degree of desperately needed strategic competence and international leadership that would provide an important course correction. But it is not clear that the U.S. would be out of the woods entirely. Some differences with allies run deeper than the current president. Indeed, a Biden administration would still face challenges managing the widening strategic divides with Saudi and Turkey, and several potential Biden administration policy objectives—from changes to U.S. nuclear use policy, to a continued focus on burden sharing—could be in tension with plugging U.S. credibility gaps and strengthening nonproliferation. 

These challenges are not insurmountable, but it would be naïve to assume that the United States can simply go back to status-quo ante. By staking out extreme positions with few political consequences—indeed, the Republican Party has embraced many of Trump’s positions—Trump has altered the terms of the debate. Trumpism—and its characteristics of retrenchment, nationalism, and hostility toward the U.S.-created international order—will survive after he leaves office and shape U.S. political discourse. An extreme oscillation between engagement and pull back from the international community is, for many allies, no more tenable than U.S. withdrawal. And this is precisely their concern: That Trump is a harbinger of things to come. That the U.S. is walking away from the international order that it built and led for more than 70 years. 

Countries do not take lightly the decision to develop nuclear weapons. However, history suggests that a total loss of confidence in U.S. security guarantees can cause allies to pursue them. It is almost impossible to know how close we are to that point now. Trumps actions certainly get us closer. 

Eric Brewer is Deputy Director and Senior Fellow at the Project on Nuclear Issues at the Center for Strategic and International Studies.