For Washington, allies have become the equivalent of Facebook friends: the more the better. Yet rarely does America consider the cost of such military commitments. Officials assume the mere threat from Washington is enough to force even the most hardened adversary to back down.

That appears to be the attitude of Secretary of State Mike Pompeo. On a recent trip to the Philippines, he threatened the People’s Republic of China with war lest it so much looks crossly at “Philippine forces, aircraft or public vessels.” Or more accurately, attack any of them, which would “trigger mutual defense obligations.” By which he meant Washington’s unilateral promise to go to war on behalf of Manila. The “mutual” in U.S. defense treaties is an inside joke; no one expects the Filipino armed services to return the favor. Philippine Foreign Secretary Teodoro Locsin, Jr. said Manila would accept America’s word, which he interpreted to mean “we have your back.”

Why make such a commitment? The secretary denounced the China “threat” and explained: “China’s island-building and military activities in the South China Sea threaten your sovereignty, security, and therefore economic livelihood, as well as that of the United States.”

His statement is false in almost every way. The PRC’s activities limit Manila’s control over a few rocky formations, not the survival of the Philippine state. Losing a tussle over those territories and surrounding natural resources would be embarrassing but have little impact on the safety or well-being of Filipinos. And such an event would have correspondingly less impact on Americans, individually or collectively. Under normal circumstances, Washington would barely notice the event.

Beijing and Manila are contesting ownership of two rocks known as Scarborough Shoal (Panatag Shoal to the Philippines and Huangyan Islets to China). Once administered by Manila, the rocks were grabbed by the People’s Republic of China in 2012, and since then the two countries have sparred over control. Additionally, another controversy involves Mischief Reef, located within the Philippine Exclusive Economic Zone, upon which China has constructed military facilities, including a runway.

The PRC behaved badly, but its claim is limited to peripheral territory, not the entire Philippines. The region is filled with such challenges. For instance, Beijing also is contesting control over elements of the Paracel and Spratly Islands with Vietnam, Malaysia, Brunei, and Taiwan, and the Senkaku/Diaoyu Islands with Japan. The specifics of each case vary, but collectively the territorial fights have triggered a nationalistic surge throughout the region.

History does not justify China, but it helps explain Beijing’s aggressive behavior. Many Chinese policymakers see their nation as only now escaping centuries of weakness and humiliation. Beijing is making up for lost time in asserting claims which a couple of decades ago appeared to be well beyond the PRC’s reach. Ironically, China is acting like the young American republic in the nineteenth century; the latter was truculent, threatening war against the United Kingdom over the Canadian border and invading Mexico to enforce dubious claims, seizing half of the latter’s territory.

Washington has no direct stake in the outcome of the Philippine-China spats, and America’s past response reflected its distance from the controversy. The United States has consistently criticized the PRC for its violent actions, but despite America’s “mutual” defense treaty with the Philippines, Washington has avoided any direct confrontation with the PRC. Moreover, Washington soft-pedaled its security commitment, to avoid giving offense to Beijing and creating an incentive for Manila to act irresponsibly.

However, Secretary Pompeo’s effusive promise replaced past caution. “What Pompeo said is what the defense establishment actually wanted to hear,” emphasized Julio Amador III of the Manila-based Asia Pacific Pathways to Progress Foundation. Said Jay Batongbacal of the Institute for Maritime Affairs and Law of the Sea: “It is significant because it is made publicly and openly by a U.S. secretary of state, and it expressly refers to applicability to the South China Sea.” He added: “This is a little bit more pointed and clearer than previous statements.”

But why? Manila is an odd “ally” to whom to make such a commitment. Early in his presidency, Phillippine president Rodrigo Duterte ostentatiously embraced China and insulted the United States. In fact, he declared his government’s “separation” from Washington and suggested sending American troops home. More recently, Filipino Defense Secretary Delfin Lorenzana warned that if Washington did not clarify the alliance’s application to Scarborough Shoal, ending the relationship was “an option.” Even if his country declined to continue accepting America’s defense subsidies, Lorenzana argued that “It is not the lack of reassurance that worries me. It is being involved in a war that we do not seek and do not want.” Indeed, he added, “If the Philippines does not want to be involved in a war, it can opt out on that basis.”

That is Manila’s right. But if the Philippines sees no reason to go along with the ally protecting it, why should America opt into a war involving Manila?

Surely not because there is an alliance. It is the sort of non-mutual “mutual defense treaty” characteristic of one made in 1951. That treaty was sixty-eight years ago—a different time, with different circumstances, different threats, and a different rationale. The original purpose was mostly to guard against a rearmed Japan, though the Soviet Union constituted a convenient secondary threat. Both of those are now gone.

The new “necessary enemy” is China. However, it makes a poor substitute for the Soviet Union. After all, Beijing is focused on regaining what it believes to be its proper due after centuries of maltreatment and humiliation. That means opposing America and its allies when they are in the way, not in every case as a matter of course. That also means China is advancing more restrained objectives—to advance itself rather than destroy its competitors. In other words, the PRC threatens Washington’s outsize regional influence, not America’s existence and liberal political order.

Although the Philippines enjoys historical and personal connections with America, the former doesn’t particularly matter for U.S. security. Historically, the Philippines have long provided a convenient way station for the U.S. Navy and an advanced base for the other armed services, but that didn’t make the archipelago vital for America’s defense. The rocks are even less vital.

Yet battling on Manila’s side, including for such a peripheral interest as the Scarborough Shoal, could lead to full-scale war—with a nuclear power. That’s an extraordinarily important, and potentially expensive, commitment. Yet there has been no public debate to justify expanding America’s guarantee.

There is a serious argument for backstopping the independence of friendly states to prevent Chinese military domination of Asia. However, that appears to be well beyond Beijing’s current capabilities and intentions. The PRC wants influence but has demonstrated no interest in conquest. Furthermore, if Beijing swallowed such disparate and distant lands, it would create an extraordinary burden on the Chinese nation which remains poor and faces many challenges.

Another problem is that America’s supposed commitment remains ill-defined. Foreign Secretary Locsin argued that “In vagueness lies the best deterrence. I don’t believe going down into the details is the way that the sincerity of the American commitment will be shown.”

However, ambiguity is potentially dangerous. Exactly what is the United States promising to protect under what circumstances? The potential for mistake and confusion is significant. Manila might act recklessly, convinced of American support. China might respond similarly, certain the United States won’t act. If that happened, such ambiguity would have helped trigger a conflict.

The best argument for American involvement in territorial disputes is to protect freedom of navigation. To assert Washington’s commitment to that principle, the Pentagon has mounted Freedom of Navigation Operations—sending ships through waters claimed by Beijing. Adding security guarantees for this purpose is a significant escalation. Said Secretary Pompeo: “I think the whole world understands that the Trump administration has made a true commitment to making sure that these seas remain open for the security of the countries in the region and the world, open to commercial transit.” However, Beijing has shown no interest in ending commerce which greatly benefits all states and peoples in the region. That would change in wartime, but then none of today’s rules would apply.

Nor does freedom of navigation warrant taking Manila’s side in its territorial dispute. There is no inherent reason to choose one side or the other, though the Philippines appears to have the better case. Anyway, American preference for Filipino control is not enough to bestow the de jure right to the islets. Washington could scarcely claim to believe in the rule of law if it sought to oust China from plausibly Chinese islands in order to shrink Chinese territorial waters. Washington’s primary interest in the shoal is to support the peaceful resolution of international disputes. But that does not warrant a willingness to fight China, especially when the latter has far more at stake than does America.

If Washington is prepared to fight, it must pay the cost. Author Mark Helprin recently declared that the United States must “alter the correlation of military forces in the Western Pacific, and indeed in the world, so that it no longer moves rapidly and inevitably in China’s favor.” Fail to do so, and “the Pacific Coast of the United States will eventually look out upon a Chinese lake.”