In 1999 the Philippine Marines ran this former U.S. Navy ship aground on a coral reef named Second Thomas Shoal in the South China Sea’s Spratly Islands archipelago. Essentially the ship acts as an ocean-going game of squatter’s rights over the not-quite-island ‘maritime feature’, and the Philippines continues re-supplying the ailing ship and the seamen who live aboard. As of late, the Chinese Coast Guard has been trying to interfere with those supply deliveries. If this dispute escalates further could draw in U.S. naval forces to direct conflict with China in aid of long-time Pinoy strategic allies.

The boat, now dubbed the BRP Sierra Madre, started life as the USS Harnett County, serving in World War II and the Vietnam War before transferring to the Republic of Vietnam Navy in 1970 as the RVNS My Tho. After moving 3,000 Vietnamese refugees to Subic Bay in the Philippines during the fall of Saigon, the ship was then transferred to Philippine ownership. Again the ship was renamed, first the BRP Dumagat, then the BRP Sierra Madre. From 1976 to 1999 it served as transport for the Philippine navy, before being run aground.

China has been trying to exert its might over the region for decades, facing opposition from not only the Philippines, but also Taiwan, Malaysia, Vietnam and Brunei. The dispute is largely in a state of diplomatic stalemate at the moment, with none of the countries escalating to violence yet. China has recently been an aggressor in the region, , dredging and relocating enough dirt to create a massive island with a big enough seaport to receive tankers.

According to reports from the Philippines, China is attempting to get the nation to abandon its claim on Second Thomas Shoal. In recent weeks it has attacked supply ships heading there with military lasers and water canons. Over the weekend a Chinese coast guard ship collided with a Philippine resupply vessel. China’s goal, it seems, is to do what it can to even prevent repairs to the ailing 80-year-old ship. If the ship begins to fall apart and decay further, China will gain control over the reef.

As the move could put pressure on the U.S. to respond.

Any move by China to seize Second Thomas Shoal would put pressure on the U.S. to back up its ally—not just diplomatically but also militarily. That could bring the U.S. into direct conflict with China, carrying huge risks for both powers. Beijing might see a window of opportunity while the U.S. is preoccupied with the wars in Ukraine and the Middle East, security analysts said.

The U.S. response to developments in the South China Sea are under greater scrutiny because of events in 2012 that scarred the alliance and caused lasting national trauma in the Philippines. That year, after a weekslong standoff between Chinese and Philippine forces, China seized . Officials in Manila said later the U.S. hadn’t done enough to support its ally, with few repercussions.

Thus far the U.S. response has been weak to non-existent. During the ramming event on Sunday, Navy destroyer USS Dewey was over the horizon “”

When asked about the land reclamation efforts by the Chinese, Fox News reports:

A U.S. military spokesman said Friday the land reclamation project on Fiery Cross Reef is one of several pursued by China but the first that could accommodate an airstrip.

“It appears that’s what they’re working towards,” Lt. Colonel Jeffery Pool told .

The U.S. opposes the Chinese land-grab and wants other governments to refrain from doing the same.

“We urge China to stop its land reclamation program, and engage in diplomatic initiatives to encourage all sides to restrain themselves in these sorts of activities,” Pool told the French wire service.

While , Beijing fastidiously maintains it has near total sovereignty over the South China Sea, and can essentially do whatever it wants. International arbitration determined .