It has become a very bad habit.

Using its might, China has been harassing oil-and-gas explorations of Southeast Asian countries in the South China Sea, a strategic waterway claimed by Beijing based on historical records, where about $3 trillion worth of sea-borne goods pass every year.

Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims over the sea, which is becoming the region’s flashpoints as other extra-regional powers, like the United States, Australia, Japan and India, are becoming interested in ensuring freedom of navigation.

More than 200 nautical miles off the coasts of Sabah in eastern Malaysia, a tense and dangerous standoff is happening as two Chinese coast guard ships circle, like sharks, around a Panamian-flagged ship, West Capella, which is drilling five oil wells for Malaysia’s national oil company, Petronas.

The situation began last year, after West Capella began its operations in October. When China’s coast guard vessels appeared in the area, Kuala Lumpur sent its Royal Navy to guard the drilling operations, forcing the lightly armed Chinese ships to back out. But the ships never left the area. They refueled and resupplied from a nearby base on the artificial island Fiery Cross in the Spratlys, in another part of the disputed South China Sea.

Much later, Vietnam, which has a similar claim in the South China Sea, joined the fray as a three-nation game of nerves emerged in the area. Vietnam’s militia vessels were also near the oil fields to assert Hanoi’s sovereign claims in the area.

China has also started harassing other Malaysian oilfields closer to Sabah’s coasts, increasing tension in the area, a reprise of what happened last year when Chinese coast guard, militia vessels and fishing boats swarmed a Vietnamese-controlled oil field contracted to Russian oil exploration company Rosneft.

China’s tactics to harass oil-and-gas exploration activities began in 2011 when two Chinese maritime patrol ships bullied a survey ship hired by Forum Energy to explore gas fields in Reed Bank, an area within the Philippines’s 200 nautical mile exclusive economic zone (EEZ) west of Palawan island.

The Philippines did not move to protect the oil-and-gas exploration activities of Philex Oil Corp. because, at that time, it lacked maritime vessels to escort survey vessels contracted by local companies to do scientific studies in waters within the Philippine territories.

The Manuel Pangilinan-controlled oil-and-gas exploration venture was forced to suspend operations due to rising political costs and a brewing regional conflict about to erupt at that time. Later. The Philippine government imposed a moratorium on all oil-and-gas activities in the disputed areas as Manila filed an arbitration case before The Hague in 2013 to seek legal basis for its economic exploration and exploitation in the Reed Bank.

In July 2016, the Permanent Court of Arbitration favored the Philippines, declaring China’s excessive claims on the South China Sea as illegal and nullifying its nine-dash-line map anchored on historical claims.

It ruled that all features in the disputed areas in South China Sea do not have a 200-nautical mile exclusive economic zone as these islands could not sustain life without adequate potable water, and were only entitled to 12-nautical-mile territorial waters under the United Nations Convention of the Law of the Sea (Unclos).

The ruling includes the rocky outcrop about 130 nautical miles west of Zambales, Scarborough Shoal, an area used by the United States Navy as an impact area for testing its naval guns when it had a large overseas base in Subic Bay.

The shoals also figured in a three-month standoff between the Philippines and China in 2012 when a Philippine Navy Offshore Patrol Vessel, BRP Gregorio del Pilar, tried to arrest Chinese fishing vessels found poaching at the shoal’s inner lagoon and collecting giant clams.

The arrival of two Chinese coast guard vessels prevented the Philippine Navy ship from towing the Chinese fishing boats to a nearby port. A Philippine Coast Guard ship replaced BRP Del Pilar as both white ships stared eye to eye for three months until Manila blinked and pulled out its maritime vessel.

China seized control of Scarborough Shoal, prevented local fishermen from getting near and attempted to reclaim the unmanned rocky outcrop, until the US stepped in and drew a red line, warning Beijing of serious consequences if it pursued a plan to expand and build a base on an area along the busy waterway.

Some sectors blamed the Americans for the loss of Scarborough to the Chinese because it did not come to aid the Aquino government in defending the territory, and others have pointed out that the US, as a deterrent force, had failed to stop China from taking control of the area.

It was even used as a strong argument to terminate the Visiting Forces Agreement with Washington because it did not serve its purpose. But it was wrong to argue that the VFA as a mechanism failed because the Americans did not lift any finger to help defend what was considered a strategic area.

The VFA is an agreement signed in 1998 to allow American servicemen to return to Philippine soil for exercises and training. It is simply a status of forces arrangement that does not require the United States to respond to an external attack, which is stipulated in the 1951 Mutual Defense Treaty, a relic of the Cold War that does not hold water in today’s geopolitical landscape.

The United States will only respond to an overt action similar to what happened in 1941 when Japanese planes bombed Philippine airfields and sent a large invasion force to occupy the country. Perhaps, the Mutual Defense Treaty must be revisited and revised to reflect current security threats to both allies.

When Rodrigo Duterte rose to power in May 2016, he further weakened the Philippine position against China’s bullying in the South China Sea. Instead of standing up against China’s harassment in the Reed Bank, Scarborough and the Spratlys where the Philippines occupies nine features, he readily agreed to a joint venture with China in the Reed Bank.

China completely recognizes Philippines’ sovereign rights over Reed Bank, conceding the area is well within its 200-nautical-mile exclusive economic zone and would agree to a 60-40 sharing of the proceeds from the rich natural gas fields.

China, however, will use its tactics against a Vietnamese oil exploration block in another part of the disputed the South China Sea, particularly in the areas where West Capella has started to drill off the coast of Sabah.

A recent decision of the Duterte administration to terminate the VFA with the US would surely embolden China to use force and intimidation in the South China Sea to get what it wants, as Washington is forced to back away from the region.

In a way, Duterte is helping China expand its anti-access and area denial (A2AD) operations by pulling the United States away from the South China Sea and allowing China to bully, intimidate and harass Southeast Asian countries trying to develop oil-and-gas fields in the disputed waters.

Southeast Asian countries must be allowed to explore and exploit resources within its 200-nautical mile exclusive economic zones and to select an entity of their own choice to have a joint venture or partnership agreements as an independent and sovereign state does.

China’s bullying must stop. The harassment must stop. it is becoming a very bad habit. It should not be tolerated.