The always troublesome South China Sea territorial dispute between China and its neighbors is heating up again. Vietnam and the Philippines currently present the principal challenges to China’s expansive claims in those waters. Unfortunately, Washington seems inclined to back those challenges, which creates the danger of entangling the United States in this emotional dispute.

Tensions flared this spring when the Philippines deployed several ships around Scarborough Shoal (which China calls Huangyan Island) to strengthen its claim. Beijing reacted harshly to that move, gradually sending numerous fishing vessels and naval-patrol boats to the area. It appeared that the bilateral quarrel was easing in June when the government of Benigno S. Aquino ordered his country’s ships to leave the area. The Chinese foreign ministry promptly praised that move as a welcome, conciliatory gesture.

But the cordial atmosphere between the two countries soon faded. Reports circulated that the Aquino government intended not only to have the Philippine ships return to the disputed waters but also that Manila would ask the United States to initiate patrols by aerial drones to monitor Chinese moves in the area. Although Aquino later denied that his government is seeking such patrols, Beijing’s reaction to the reports was just short of furious. An editorial in China Daily accused Manila of being “obsessed with playing the role of troublemaker in the South China Sea.” The latest episode, the editorial went on, “shows Manila is determined to drag Washington into its maritime dispute with China. By seeking backup from the U.S. in its quarrel with Beijing, Manila has ignored the goodwill shown by Beijing and is trying hard to complicate the issue.”

Unfortunately, Washington’s behavior over the past year gives some credibility to China’s accusations. While attending an economic summit in Bali in November 2011, President Obama went out of his way to highlight the importance of the U.S. defense alliance with the Philippines and pledged to strengthen the relationship. Chinese officials considered his comment worrisome because it immediately followed Secretary of State Clinton’s strongly pro-Philippines statements regarding the rival claims in the South China Sea. “Any nation with a claim has a right to exert it,” Clinton said during a visit to Manila on November 16, “but they do not have a right to pursue it through intimidation or coercion.” She added that “the United States will always be in the corner of the Philippines and we will stand and fight with you.” The Obama administration backed up such rhetoric in early 2012 with a decision to deploy additional troops to that country—ostensibly to assist the Manila government in combating terrorism.

Such rhetorical meddling is especially troubling because the United States has a defense treaty with the Philippines. If Chinese and Philippine forces ever come to blows in the South China Sea, Washington is going to be in an awkward and dangerous position. There certainly will be pressure, both from domestic hawks and other U.S. allies in East Asia, not to appease China. But the potential damage to the crucial bilateral relationship with China if the United States chose to back the Philippines militarily—even if outright war could be averted—is enormous.

As the world’s leading maritime power, the United States is understandably concerned about the South China Sea territorial dispute—especially China’s breathtaking claims to well over half of the waters. Beijing’s position has important economic and strategic implications. Many of the crucial oceanic routes leading to Japan, South Korea and other countries in East Asia run through the South China Sea. Chinese control of that body of water would give Beijing a grip on the economic jugulars of all of those nations and might cause Washington’s East Asian allies to reassess their close ties to the United States.

Nevertheless, the Obama administration should be wary of embroiling the United States in the South China Sea dispute by reflexively backing Manila’s position. It would not be the first time that a small client state, emboldened by the perceived backing of a large, powerful patron, managed to entangle that patron in a dangerous quarrel. Washington needs to back off.