Why have the United States and Philippines issued defence treaty guidelines?

Following Manila’s repeated requests to clarify the terms of their 1951 Mutual Defense Treaty, Washington and Manila have agreed on new guidelines.

Why did Philippines want clarification?
Manila has claimed that the seven-decade-old treaty requires revising to reflect a changed global security environment, despite the US’s “ironclad” defense relationship.

President Ferdinand Marcos Jr., who is in Washington this week, maintained his effort as the Philippines complains of Chinese coast guard and fishing vessels suspected of maritime militia aggression in the South China Sea.

The Philippines, which imports a lot of energy, wants to harness natural gas reserves in its EEZ, which China also claims.

The Philippines wants China to back off and a strong commitment from its former colonial master to save it.

What changed?
The Pentagon now states that mutual defense agreements would apply if any country was attacked “anywhere in the South China Sea”. Coastguard vessels are also protected.

“Asymmetric, hybrid, irregular warfare and grey zone tactics” require cooperation.

China’s coast guard and fishing fleet deploy “grey zone tactics” to assert its huge territorial claims in the South China Sea through blockades, intimidation, and disruption of fishing and energy exploration.

China claims their coast guard is legal.

Why now?
China tensions are rising. Last month, the Philippines accused China’s coast guard of “dangerous manoeuvres” and “aggressive tactics” while patrolling near the Second Thomas Shoal, a shoal defended by a small Filipino navy unit 105 nautical miles (195 km) off its coast.

The Philippines said that a Chinese ship had fired a military-grade laser at one of its naval resupply vessels in February.

After smaller boats were rammed, blocked, or blasted by the Chinese coast guard and fishermen, the Philippines and some of its neighbors have complained.

China, which claims control over islands, reefs, and waterways as far as 1,500 km (932 miles) off its coast, including in five neighboring EEZs, routinely accuses foreign vessels of provocations or trespassing.

WHAT DOES THIS DO?
Knowing that the US is treaty-bound to act may prevent Beijing from confronting U.S. forces in the South China Sea, particularly its coast guard.

However, China could use its vessels to test the U.S. defense commitment and undermine the alliance, putting Washington in a difficult position where it may be afraid to intervene for fear of escalation or miscalculation.

Some commentators believe a more ambiguous mutual defense treaty would benefit the Philippines and US.