Taiwan wonder if the US will help if Vietnam attack Taiping Island.
After current mass reclamation of reefs by China, Itu Aba (Taiping) Island became less significant to China but more important to the United States. The Itu Aba Island would be useful to China only if 'Nine-Dash Line' were overthrown, and since Itu Aba Island's EEZ probably cover all Chinese occupied reefs in Spratlys, it would still make Chinese reclamation of reefs legit under 'One China'.
During the recent April 2014 low key Taiwanese naval exercise to retake Itu Aba Island simulation, Taiwanese military was asked by the media regarding what would it take to retake the island if Vietnam has captured the island. The answer was that it would take about half of all Taiwanese naval power to retake this 0.49 sq km island since Taiwanese navy would not have the support of its air force due to the great distance from Taiwan and Itu Aba Island is within the strike distance of Vietnamese Su-27s and possibly have to deal with its newly acquired Russian submarines. The French built Mistral-class amphibious assault ships would be an interesting addition to ROCN to operate in SCS if the French didn't want to deliver them to Russia, and since Taiwanese army has many U.S. made helicopters, a heli-carrier would be useful.
In 2011, when Hilary Clinton was still Secretary of State, she rushed to Beijing and had a meeting with PRC leaders discussing what would China do if Vietnam were to attack Itu Aba Island, and expected response was China would treat Itu Aba Island as one of its own. So popular belief is if Vietnam were to invade Itu Aba Island, China would have the excuse to take Itu Aba Island and attack all other Vietnamese occupied Spratly islands. Just like the Johnson South Reef skirmish of 1988, where resulted 70 Vietnamese soldiers death and China gained 6-7 reefs, including the upmost important future PLA base in Spratlys, Fiery Cross Reef. In the event of Chinese PLA intervention after Vietnam invaded Itu Aba Island: Will China return Itu Aba Island back to Taiwanese control after kicking Vietnamese off the island?
Both Itu Aba Island and Pratas (Tungsha) Island are administered by Taiwan (ROC). According to Taiwanese media, they were protected by U.S. military during the Cold War era for 60+ years. U.S. actually encourged Taiwan to occupy these 2 islands and use them as observation posts and share their intelligences with U.S. military. After the 2001 incident of U.S. EP-3 plane collided with PLAN J-8 fighter and forced landing in Hainan Island, U.S. asked the then Taiwanese President Chen Shui-bian to build a 1,200 meter long runway on Itu Aba Island and trained ROC Navy scuba divers in coordinated sea rescue just in case U.S. plane crashes in SCS again. Now according to PRC media, U.S. once again asked Taiwan to build a naval port big enough to accommodate 3,000-tonne naval frigates and coastguard cutters while improvements are being made to the 1,200-metre (3,940-foot) long runway for its Hercules C-130 transport planes. So that is why we only hear Vietnam crying foul regarding Taiwan building port on Itu Aba Island and not from China nor the U.S.
Both Itu Aba Island and Pratas Island were occupied by the Japanese during WWII. "The Japanese Navy utilized Pratas Island as a weather station and listening outpost until May 29, 1945 when a landing party consisting of Australian commandos and US naval personnel from the submarine USS Bluegill raised the US flag and declared the island as a United States territory and named it Bluegill Island." After the war, it was restored to ROC. Pratas Island is strategically situated 340 kilometers south east of Hong Kong at the entrance to Taiwan Strait and Luzon Strait. I wonder if it was so strategically important to China, why didn't China invade it just like Paracel Islands. Probably because it once was U.S. territory, and according to international military laws, U.S. could militarily intervene. Currently Pratas Island is Taiwan's first marine national park. Now according to recent SCS maps, Pratas Island is sitting on a rich patch of gas and oil fields and there are already quite a few PRC oil rigs near Pratas Island:
