America’s Strategy of Ambiguity Is Ending Now

The election of Lai Ching-te as Taiwan’s president will reawaken old debates about “strategic ambiguity.” The Biden administration has stuck with its approach of keeping vague any scenarios for intervention in a conflict with China over the island. Advocates say this enigmatic ploy keeps Beijing and Taipei on their toes, deterring the former while ensuring the latter does not act rashly. Critics suggest that “strategic clarity,” meaning spelling out when the United States might act, would do more to deter Beijing. President Joe Biden himself has spread confusion, promising in public that the U.S would intervene to support Taiwan and leaving his officials scrambling to explain that official policy has not changed.

This question of ambiguity then brings into focus a wider challenge over the nature of U.S. security guarantees in an era of rising geopolitical friction. Washington’s alliance network—it has more than 50 formal such relationships—is a formidable asset in its tussle with China. It has a number of quasi-allies, too, such as Taiwan, as well as close partners, like India, Singapore, and Vietnam. All of these come with commitments, either explicit or implied.

Yet Washington’s credibility to deliver on them is under growing pressure in the eyes of adversaries and allies alike. It is likely to have to demonstrate its capabilities more often—in effect making its guarantees less ambiguous—putting further strain on an already overstretched U.S. military.

The fact that the United States risks overstretch should be clear from recent developments. Biden brims with confidence about Washington’s ability to meet its global obligations. But the combination of Russia’s war in Ukraine and the ongoing crisis in the Middle East raises obvious questions about distraction and stretched resources. Recent attempts to calm relations with China speak to a strong desire to ensure Asian calm, especially in a U.S. election year.

Examples of anxious Asian allies are not hard to find. The Philippines is one. Manila has tangled of late with China in the South China Sea. Beijing has tried to block missions to resupply a rusting World War II-era ship in Second Thomas Shoal, which Manila grounded to mark its territory in 1999. Philippine President Ferdinand Marcos Jr. has asked the United States to give guarantees that attempts by China to retake the shoal would trigger U.S. alliance commitments, which Washington has duly done. In recent weeks, the United States deployed a Nimitz-class aircraft carrier, the USS Carl Vinson, to sail with the Philippine Navy.

South Korea is another case, given fretting in Seoul about threats from the north. Not long ago, South Korean President Yoon Suk-yeol mused that Seoul might need to develop a nuclear deterrent, a signal of unhappiness about Washington’s nuclear umbrella. Last April, the United States and South Korea signed the Washington Declaration, a pact that, among other things, promised to strengthen and make more explicit U.S. extended deterrence commitments. The deal involves the United States sending a nuclear-armed submarine to South Korea for the first time in a generation, along with nuclear-capable bombers.

The fact that the United States often has to demonstrate capabilities—and thus reassure allies by actions, not promises—is not exactly new. Under President Barack Obama, the United States grappled with how to respond to China’s campaign of artificial island-building in the South China Sea. This followed a tense standoff between China and the Philippines after Beijing seized Scarborough Shoal in 2012. Sensing that its credibility was under threat, Obama’s administration began freedom of navigation operations, sailing military vessels close to disputed maritime features, simply to prove that it could. These maneuvers are now a core part of U.S. strategy to reassure the region. Two were conducted by the U.S. Navy’s 7th Fleet last November, for example, in the South China Sea and the Taiwan Strait, respectively.

Yet three factors suggest the United States will now need to demonstrate similar capabilities more often, the first being a deteriorating global and regional military balance. In the decades after the Cold War, Washington enjoyed undeniable military superiority, and thus rarely had to show it off. Now in Asia, it must contend with China’s vast military buildup. This is especially so in the maritime domain, where China now boasts a substantially larger navy as measured by number of vessels.

The second factor reflects a change in U.S. strategy. Biden’s team talks a lot about “allies and partners.” This often means asking close allies, such as Australia and Japan, to do more to contribute to collective deterrence and security. U.S. National Security Advisor Jake Sullivan recently wrote about developing a “self-reinforcing latticework of cooperation,” in which U.S. friends cooperate more with one another, as well as with Washington.

The nature of U.S. security ties in the Indo-Pacific is therefore changing. Rather than following a NATO-like approach, U.S. links in Asia were set up with a “hub and spoke” model. These narrow bilateral agreements were originally designed in part to constrain pro-Western but potentially trigger-happy autocrats in countries like the Philippines, South Korea, and Taiwan. Today, to cope with China, the United States is being forced to create a more collective model of security, interspersed with new mini-laterial groupings, such as AUKUS and the Quadrilateral Security Dialogue. The more important all of these relationships become, the more incentive China also has to test what the United States is willing to do to support those within them, in addition to its formal alliances.

The third factor is perhaps the most obvious: Donald Trump. This year will be one of rising anxiety in Asia about U.S. credibility, given the prospect of the former president’s return. Many in Asia were supportive of Trump’s tough approach to China. But they also remember his combative approach to allies, too. Viewed from Manila, Seoul, and Tokyo, the year ahead will raise all kinds of doubts about whether existing U.S. commitments will still stand if he retakes office. They will want less ambiguity, and more clarity, as a result.

All of this requires a tricky balancing act. Making ambiguous commitments more explicit is no panacea. On Taiwan, Biden’s team shows no signs of being persuaded that “strategic clarity” is wise. Both ambiguity and clarity can create perverse incentives. An ambiguous policy can push China to test to see what the red lines underneath really are. More explicit guarantees might even reduce deterrence, as former White House official Ivan Kanapathy has noted, as such guarantees can give China something to aim at, too. The “conditionalities in such a declaration, by circumscribing geographic and political limits, would invite China to exploit those very seams, challenging U.S. credibility,” he wrote in Foreign Policy in 2022.

Either way, a world in which allies want the United States to show, not tell, implies greater demands on an already stretched military. This suggests two broad options for Washington. One is to focus resources, in effect offering fewer guarantees to fewer people, and thus bolstering the credibility of those that remain. Historian Paul Kennedy recently predicted this path in an essay reflecting on the 35th anniversary of the publication of his book The Rise and Fall of the Great Powers. “The American security blanket will be tighter, smaller, limited to those well-known places such as NATO-Europe, Japan, Australia, Israel, Korea, maybe Taiwan, and not much else,” he wrote in the New Statesman.

Perhaps. But so far Biden, at least, shows few signs of dialing back commitments. Quite the opposite, in fact. This leaves a second path, namely spending more on defense and demonstrating the results of that investment more often. Biden recently signed a new $886 billion military budget. Yet even this seemingly massive figure is much lower as a proportion of national income than during the last period of geopolitical rivalry during the Cold War. “The way in which the United States has conceived itself in terms of national security is no longer viable,” former U.S. Treasury Secretary Larry Summers told Bloomberg TV recently. “We are going to have to invest substantially more in all aspects of national security.”

The obvious risk is that the United States ducks this hard choice, neither paring back its commitments nor spending enough to meet them. That might work for a while. But Washington will still find itself under pressure to do more to reassure anxious allies concerned about overstretch, waning collective security, and political instability at home. Self-evidently, the United States cannot meet its obligations to 50 allies at once, much in the same way that a bank cannot return all its deposits in one go. Its ability to do so depends crucially on ensuring sufficient confidence to avoid the geopolitical equivalent of a bank run. That prospect is remote for now. But it would be still better to avoid even a hint of ambiguity about Washington’s determination to avoid it in the future.