But we can hardly fight for the Philippines. We can only fight with the Philippines.
The Philippines are working to make sure they can fight:
THE Armed Forces is acquiring two frigates from Italy, and these are expected to increase the Navy’s capability in protecting the country’s interest in the West Philippine Sea (South China Sea). ...
Manalo also disclosed that government is inclined to acquire T-50 fighter planes from South Korea, to modernize the capability of the Air Force. A proposal has been submitted to President Aquino, he said.
We don't expect the Philippines to defeat China. We do expect them to fight if they have to.
UPDATE: More on the Philippines arms build up:
Philippines President Benigno Aquino said 23 July 2012 that the country is moving to expand its military capabilities but noted that the country wasn't preparing for a fight over the South China Sea. In his annual state of the nation address to the Congress, Aquino urged lawmakers to pass an Armed Forces modernization bill that would add 75 billion pesos ($1.8 billion) for defense spending over the following five years to acquire more weapons, personnel carriers, frigates and aircraft. Aquino announced that more than 40 military aircraft including attack helicopters and two newly refurbished C-130 cargo planes and other weapons will be delivered in the coming two years to bolster Philippine military. President Aquino also announced that in 2013, "10 attack helicopters, two naval helicopters, two light aircraft, one frigate and air force protection equipment will also be arriving. At this moment, the armed forces are canvassing equipment such as cannons, personnel carriers and [additional] frigates." ...
Apparently, a modest modernization program was the first step necessary to gain respect from the Philippines neighbors and be a worthy member of any security alliance. Once the Philippines was able to project a credible armed forces, it could then work in synchrony with the armed forces of other countries in deterring would-be military adventurism and in performing peace operation efforts for the international community. In addition, a credible armed force would mean a capable force that could effectively support the Philippine government�s diplomatic efforts in addressing contemporary security concerns as territorial conflicts and maritime disputes, as well as threats of transnational nature such as piracy, poaching, smuggling, and environmental pollution.
Let's hope the Philippines carries this out.
The article notes that while America had bases in the Philippines, their government could afford to downgrade their naval and air power to focus on defeating communist insurgents.
Belatedly, the Philippines is realizing that America no longer stands in the way of potential enemies.
In regard to Manila's defense priorities, we have had an impact since we were asked to leave after the Cold War. After 9/11, we assisted the Philippines government in fighting jihadis inside their country. That success was not achieved in isolation against Moslem separatist insurgents, so the internal military challenges aren't anywhere near as great as they once were. Communist insurgents have faltered, too. Which allows President Aquino to ask for weapons mostly designed to shore up air and naval power.
As they know, the Philippines can hardly defeat a serious Chinese effort to settle territorial disputes by force. But Manila can make sure that if China wants to settle territorial disputes by force, China will have to make a more serious effort.
And anything that compels China to use enough force to get the world's attention (and America's) will help deter the use of force in the first place.