A worker adjusts the U.S. flag before Japanese Prime Minister Abe addresses media following a meeting with President-elect Trump in New York City on November 17, 2016. Andrew Kelly / Reuters

Before November 8, there were few assurances more sacrosanct than Washington’s guarantee to safeguard the security and stability of its allies across the Asia-Pacific. Since its days of imperial expansion in the Philippines and through World War II, the United States has helped preserve rule-based order in the Pacific. In 1950, then-Secretary of State Dean Acheson formally declared that the United States would defend Japan and the Philippines, creating a zone of protection that would ultimately encompass Taiwan and South Korea. Through the 20th century, the United States emerged as the dominant power in the region, with permanent military bases in Japan, South Korea, and elsewhere.

After November 8, in the coming age of Donald Trump, uncertainty over Washington’s role in the Pacific reigns supreme. During his presidential campaign, Trump challenged decades of bipartisan foreign-policy consensus, arguing that the United States should strongly reconsider defending its allies—everyone from its NATO partners currently under threat from Russian aggression, to Asian allies like South Korea and Japan worried about a nuclear-armed North Korea and a rising China. In stump speeches, he said that Washington was paying far too much to protect South Korea and Japan, and that, instead, these nations should develop their own nuclear weapons rather than relying on Washington. (Trump has since denied having said this.) “If somebody attacks Japan we have to go and start World War III, okay? If we get attacked Japan doesn’t have to help us,” he warned at a rally.

Now, South Korea, Japan, Australia, Vietnam, and others are assessing whether Trump intends to deliver on his rhetoric. Both President Shinzo Abe of Japan and South Korean President Park Geun-Hye called Trump immediately after his victory to assert the importance of their alliances with the United States, with Abe becoming the first foreign leader to huddle with Donald Trump at his gold-plated meeting room at Trump Tower in New York last Thursday. Though Abe disclosed few details about what they discussed, he described their exchange as “candid,” and expressed confidence that “Trump is a trustworthy leader.”

Until Trump’s foreign-policy team is fully assembled, it won’t be clear whether or how his isolationist inclinations will translate into actual policy, especially given that, unlike traditional American isolationists, he also wants to massively expand the country’s military might. With Trump perhaps prepared to upend the post-war liberal order, how countries across the Pacific respond to the potential sudden power vacuum opened up by a U.S. withdrawal will determine whether the region falls under the sway of China, or instead engages in an arms race as countries that depended on Washington for security look to protect themselves.

The first challenge awaiting Abe and other Asian leaders is the confounding question of whether Trump simply said whatever he thought it took to win. In a manifesto published in Foreign Policy two days before the election, Alexander Gray and Peter Navarro, two of the president-elect’s advisors, offered a rough sketch of what a Trump Asia policy could look like: containing China’s rise by investing more money in the U.S. military, while drawing closer to regional partners like Thailand, who, under the Obama administration, were held at arms length over their poor human-rights records. A relatively conventional-sounding Republican foreign policy such as this would differ sharply from the isolationist vision Trump articulated on the trail. If this is the course he pursues, Pacific nations currently hosting U.S. troops may need make only minor adjustments.

“These northeast Asian allies might have to buy into [the idea of] Trump the deal maker and try to give him a better deal,” Brian Harding, director for East and Southeast Asia for the National Security and International Policy team at the Center for American Progress, suggested. “I’ve been telling the Japanese government for a year, if Donald Trump is elected they need to throw a billion dollars at something,” such as increasing Japanese government funding to host U.S. troops, he added.

Foreign-policy experts like Aaron Connelly, a research fellow in the East Asia Program at the Lowy Institute for International Policy, note that while the United States has often raised cost-sharing concerns with its allies, the tribute-like system Trump has outlined represents a serious break from tradition. “We’ve never handled our alliance system like a protection racket. … We’ve always handled cost-sharing from the perspective of two allies engaged in a common effort to ensure peace and stability in the region,” Connelly said. But at least the protection-racket rhetoric assumes that the United States will continue to play a role defending allies in the region. Assuming the allies pay up.

The other possibility, of course, is that Trump will upend every norm of the post-war liberal world order by drawing down America’s vast, Pacific-based military resources. There are at least 80,000 U.S. military personnel permanently stationed in Japan and South Korea, with thousands more regularly rotating through the Philippines. The Japan-based seventh fleet includes an aircraft carrier, 80 other vessels, and 140 aircraft. This year, in an effort to check China, the United States began shifting resources from fleets based in the continental United States to Japan as well.  “If [Trump’s] comments could be just dismissed as a flash in the pan, as we say in Australia, that would be one thing. The reality is his views on the Japan alliance go way [back] to the 1980s. And they are very consistent and they are pretty critical and hostile,” said Andrew Shearer, a senior advisor on Asia Pacific security at the Center for International and Strategic Studies in Washington, and a former national security advisor to two Australian prime ministers.

But there’s a risk of a more fundamental rupture. Richard Javad Heydarian, a political science professor at Manila’s De La Salle University, said the election results cast into question the maturity of American democracy. No matter what shape Trump’s foreign policy takes, Asian countries will consider it significant that an electoral majority of Americans (if not a popular majority) voted for an inexperienced candidate who advocated withdrawing from U.S. treaty allies. “Many allies are deeply worried about what will come next next,” Heydarian said. Iain Henry, a Ph.D. candidate at Australian National University who researches how American allies assess the United States’ reliability, said that Trump’s election, “thrust into public view that there is a shift in Asia. There’s not a decline in American military power but allies fear there’s a decline in America’s willingness to use it to defend certain interests.”

If Trump shows no interest in defending America’s Pacific allies from China, they’ll have to quickly choose how to realign themselves. They could bind themselves close to China and relent over points of tension, such as the ongoing territorial conflict over sovereignty in the South China Sea. International relations scholars call this stance “bandwagoning,” or giving in to a powerful state in the hope of receiving better terms in the relationship. This, for example, is the tack that Rodrigo Duterte, president of the Philippines, appears to be taking toward China, based in part on the calculation that Washington’s promises to protect his country from Chinese aggression are insincere. Duterte “has always been doubtful of American intentions in the Philippines. And [that includes] its commitment to defend Philippine interests in the South China Sea, including the Scarborough Shoal,” Heydarian said. Duterte has suggested that the Philippines has little chance in a war with powerful China anyway. “I am not ready to commit soldiers of this country just to be massacred” against China, Duterte has said.

But large, powerful states that refuse to submit to China have little interest in bandwagoning. For them, it is a question of balancing: Dealing with America’s potential absence by building up alternative paths of resistance to China—stronger alliances with others threatened by China’s rise, or upgrading domestic defense capabilities to resist China, absent U.S. assistance. India may already be pursuing such a strategy. On a visit to Japan two days after Trump’s victory, Prime Minister Narendra Modi announced that plans were in motion to purchase amphibious vessels from the country, and share advanced civil-nuclear technology. Domestically, Abe has improved Japan’s military readiness by lobbying parliament to dramatically increase funding for the Japanese military, in addition to reinterpreting post-World War II restrictions to allow its troops to fight overseas.

In moderation, such balancing behavior could be good for the United States, which has long pushed for its allies to enhance their military readiness. After all, Trump’s contention that many U.S. allies don’t pay their fair share is hardly a fringe one; President Obama has delivered similar critiques. (Unlike Trump, though, he never threatened to abandon allies that failed to pay for more of their own military.)

But the pursuit of balance against China could quickly spark a regional arms race. China could respond to an increase in Japanese and South Korean military funding, exacerbating tensions across the Pacific, increasing the likelihood of a confrontation. Washington would then have to decide whether to intervene in a regional military dispute where China is one of the key players. An even bigger concern is that Japan and South Korea may take Trump at his word, and decide to develop a nuclear deterrent to China and North Korea. “That’s a huge deal for the Japanese and Koreans who are probably reeling right now with the reality of Trump as president,” Shearer said. Indeed: A November 15 editorial in the Korea Herald, South Korea’s largest English-language newspaper, said that in light of Trump’s victory, the government should begin developing “weapons-grade plutonium” to “mitigate the impact of a potentially less-committed alliance partner.”

There is historical precedent for allied nations pursuing nuclear weapons during periods of waning American interest in Asia. Henry pointed out that South Korea and Taiwan both developed nuclear weapons programs in the 1970s after fears that U.S. withdrawal from Vietnam signaled a wider American abandonment of Asia. “When states doubt American reliability they don’t sit still. They will do something to mitigate the security risk it poses,” Henry said.

A decision by South Korea or Japan to develop nuclear weapons could, in turn, prompt a pre-emptive response from either North Korea or China, and lead others to conclude that a nuclear arsenal is the only way to guarantee their security, spurring yet more nuclear proliferation. It would also present U.S. policymakers with a dilemma. If they assented to a nuclear-armed South Korea and Japan, over Chinese opposition, it would put Washington—which only just completed the long-gestating Iran nuclear deal—in a hypocritical bind.

To state the obvious: Whatever the advantages of a nuclear-capable South Korea and Japan, they would be undermined by the potential chaos of a nuclear-buildup. “There are strong and clear reasons for a policy of non-proliferation,” Connelly said.

The Trump team plans to alleviate any anxieties over its plans for Asia by scaling up investment in the American military, including expanding the ranks of the army by 90,000, and increasing the naval fleet by 40 ships to 350. “He’s going to be facing Putin with a nation that is not diminishing its military, but a country that is dramatically increasing it to Reagan-like levels,” Trump surrogate Rudy Giuliani said recently.

But no analysts I spoke with believed that extra ships, on their own, would offer the security guarantee the region seeks, especially given Trump’s anti-trade rhetoric and the tanking of the Trans-Pacific Partnership. “The credibility of alliance is not measured solely by military power,” Evan Laksmana, a researcher at the Center for Strategic and International Studies, in Jakarta, explained. American investment in trade agreements and regional multilateral institutions would be more effective ways for the United States to reassure its Asian allies, he said. “The military buildup is not long term. No one is under the illusion that the U.S. will always continue to put more military in the region.” Connelly agreed. “Trump's advisors seem to be using ship count to send a signal of American commitment to the region, but allies and rivals are unlikely to adopt radically different strategies in response to the navy going to either 312 ships or 350 ships.”

What we can say for certain at this point is that Trump’s Asia reset will entail a vast array of possibilities. As Henry Kissinger, who recently met with Trump, told Jeffrey Goldberg, foreign powers will engage in “a frenzy of studying” to figure out what foreign policy course Trump intends to take. Uncertainty, a trait Trump has repeatedly praised, will be the state of things.

Katsuyuki Kawai, an advisor to President Abe, struck a hopeful note about the strength of the U.S.-Japan relationship in an interview with Reuters during Abe’s visit with Trump. “[W]e don’t have to take each word that Mr. Trump said publicly literally," Kawai said. The question for Asian allies, along with everyone else, remains how exactly to take the president-elect’s words.

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