The “rebalance” isn’t working. Washington wants to ensure the survival of an order in Asia where it sits at the head of the table, and China pursues her interests in a way her neighbors can live with. But that hope is slipping away. To give us the best chance of the United States maintaining a strong and sustainable position in Asia, President Obama needs to decide what he really wants, and what he can live without. In his West Point speech last week, we saw a glimmer of that realization from the president.

So far, Obama has tried to manage Beijing by taking a middle road between reassurance and deterrence. Too soft an approach would invite revisionism, goes the line, and being too assertive would accelerate the trend towards a deeply adversarial relationship. He took a conciliatory line at the Sunnylands Summit, resisted Japanese calls to take a harder line on China in the Senkaku/Diaoyu islands through most of last year, and the administration, in the form of the vice president, was notably cordial in visits to Beijing, including right after the ADIZ declaration at the end of 2013.

On the other hand, in April, he made his own statement that the United States would fight to defend the Senkakus, is building up its military presence in the Philippines and has worked to strengthen its partnerships in the region. He also added that the Pacific hosts the bulk of U.S. military assets. America’s target is to have 60 percent of Air and Naval forces in the Pacific by 2020—those services are necessary for a presence in Asia and have been partially shielded from budgetary pressure. Just last week at the Shangri-La Dialogue in Singapore, Defense Secretary Chuck Hagel, in harmony with Japan’s Prime Minister Shinzo Abe, took a firm line on China.

But it’s not working. China has accelerated its efforts to assert control in contested areas of the South China Sea, including in waters where claims overlap with Vietnam and the Philippines. Beijing has strengthened its position in the East China Sea, successfully establishing an ADIZ over much of the area, including the disputed islands. The news is replete with specifics. In recent weeks, China has sent an oil rig to the waters south of Hainan, apparently begun building an airstrip in Johnson South Reef in the Spratly islands, and scrambled SU-27s to intercept Japanese military aircraft in the East China Sea ADIZ.

President Obama’s approach has failed to convince Beijing of the benefits of abiding by the status quo, or that seeking to alter it will incur unacceptable costs. If Asia continues on its present strategic trajectory, China will become more adventurous in seeking to cement its claims to disputed territory, and tension between Beijing and Washington will continue to deepen. That would be a disaster for both Asian and American interests.

The administration has hoped that Beijing will think that everything in Asia is important to America—from overlapping maritime claims with Vietnam to Japanese sovereignty. But from Beijing, it looks possible that nothing in Asia is that important to America, or at least not important enough to go to war with China over. Whether that’s accurate or not, it’s a thought that is slowly creeping into the minds of some of America’s allies too—and it has them worried.

There is a danger that this thinking at cross-purposes could precipitate a crisis, and that crisis could turn into a war. China might cross an actual American redline, which ironically, the White House won’t have articulated clearly enough to avoid antagonizing Beijing.

If Washington wants to mitigate this risk, and to seek to change the current strategic trajectory, it will need to identify those issues it would really go to war with China over. Writing that list will be a painful process, because of how much we all care about some things that must be left off. And there will be costs to this approach—it will be easier to make credible undertakings about things that are on the list, but harder to do so about things that are not.

In paragraphs nineteen and twenty of last week’s West Point speech, the president acknowledged the need for that list, although without a specific mention of China. He said “The United States will use military force, unilaterally if necessary, when our core interests demand it”. In the next paragraph he said “…When issues of global concern that do not pose a direct threat to the United States are at stake… the threshold of military action must be higher.” It’s a vital point. Now he has to write that list of core interests, not just admit that it’s important.

The most painful exclusion will be Taiwan. America cannot prevent China taking control of the island eventually, one way or another. That means it’s important to leave Taiwan off the list, because America’s position in Asia is only weakened by making a security guarantee that isn’t credible—that’s why Ukraine never made it into NATO.

Other things would be left off, too. Beijing’s border disputes with non–U.S. allies would not be Washington’s problem. Hanoi is on its own, Manila and Tokyo are not. Then there are some tricky cases; should America go to war with China if Beijing attempts to change a previously agreed boundary?

Not all the answers are obvious, but we need them before a crisis materializes. Otherwise, America and her allies in Asia may find themselves bearing the risk of a policy of deterrence without the deterrent effect. That’s a bad deal, and Obama knows it. When the stakes are as high as they are in Asia, it is no longer prudent to be prepared to go to war for marginal interests, nor to tactfully avoid expressing resolve over things that really matter.

This doesn’t mean abandoning America’s values or the rules-based order she has presided over, which has been so important for Asia. But by drawing a distinction between those things it does promise to fight for (like Japan’s sovereignty) and those things it does not (like a more tactful approach to sovereignty claims from Beijing), Washington can approach these types of concerns differently.

By uncoupling America’s core interests from its preferences, Washington’s commitments to its allies will be less vulnerable to lower-order issues in the region. America would also be free to be more vocal on marginal issues without as much risk of escalation.

There’s a second important element. By admitting flexibility where it exists in practice, America would have a basis for genuine dialogue with China, rather than simply trying to convince Beijing to accept Washington’s preferred outcomes. And by drawing up the list carefully, core interests would be kept off the table.

What more potent way to show that Obama understands the “new model of great-power relations” than a serious discussion about the future of Taiwan, with necessary deference to China’s interests? If America can’t hope to decide the future of Taiwan anyway, what are we really giving up? Dialogue at that level may help to create an Asia in which China has a greater stake in participating in the system than in remaking it.

President Obama has conceded some things are worth going to war over, and some things aren’t—even important things. Drawing up that list now will provide the basis for stronger deterrence, and more substantive dialogue with China. That’s the strongest foundation for America’s continued role in Asia. Maintaining that role is the United States’ most important foreign-policy objective—and nothing could be better for the region.

Harry White is an analyst at the Australian Strategic Policy Institute (ASPI); these views are his own. Follow him on Twitter: @HarryEWWhite.

Image: Flickr/Official U.S. Air Force/CC by-nc 2.0