The arbitral tribunal's ruling that Taiping Island, 0.51 square kilometer in area and the largest island in the South China Sea, is a "rock" rather than an "island" sparked public outcries in Taiwan. Sixty-two percent of the people wished Taiwan leader Tsai Ing-wen could visit the island to demonstrate Taiwan's defiance to the ruling.

The South China Sea issue was not Tsai's priority. So far she has eschewed China's historic rights in the South China Sea and the implications of the dotted line so as to distance herself from the position of the Chinese mainland. But overwhelming public resentment against the ruling gave her no choice but to denounce it as "totally unacceptable".

Tsai's first priority, realistically, is the economy, which depends heavily on the mainland. The poor performance by her predecessor Ma Ying-jeou on the economic front tells why Taiwan residents selected her - for a change. Her second priority is to break the cross-Straits impasse. The mainland insists that exchanges are possible only if she accepts the 1992 Consensus on one China. So far her attitude has been one of studied ambiguity.

Here is the chance. The protest in Taiwan over the ruling, in fact, resonates with that of the mainland. She could use this to respond positively to public opinions across the Straits. The only price to pay is the pressure from the United States and Japan, neither of which wants her to stress China's historic rights in the South China Sea, let alone join hands with the mainland on the sovereignty issue. But Tsai could still maneuver her move by citing the obvious loophole in the ruling and the overwhelming public opinion. This is a price she can afford.

She could, in the first place, heed the public opinion to visit Taiping Island. Her predecessors Chiang Ching-Kuo, Chen Shui-bian, Ma Ying-jeou did so while in office. The one who didn't is Lee Teng-hui. She could show that she is no less determined on China's sovereignty. And she could make a difference. If she visits two months after taking office, it will be impressive. Ma visited the island only toward the end of his tenure. Apparently didn't need to bother about US disapproval any more.

Tsai could make position of Taiwan on the South China Sea clearer. A day after the ruling, she stood on Di Hua frigate and said: "Now is the time for us to demonstrate our resolve to safeguard the country's interests." But her remarks that the frigate's upcoming patrol "carries special significance as new changes just occurred yesterday (July 12) in the South China Sea" sound more like a concealed analogy.

In contrast, Ma made it crystal clear on Taiping Island that the sovereignty of Nansha, Xisha, Zhongsha, Dongsha islands and their surrounding waters is beyond doubt Chinese. Ma also elaborated how islands in the South China Sea had been included in the coastal defense system since 1721 during the Qing Dynasty (1644-1911) and how, legally speaking, the island was not a rock at all.

Also, Tsai could strengthen the defense of Taiping Island, organize more frigate patrols and even drills in the South China Sea. She could even take the boldest step - allow scholars from the mainland to use the archives on the South China Sea in Taiwan. Most of the archives were shipped to Taiwan when Kuomintang withdrew from the mainland. Historians and legal experts across the Straits could hold workshops or seminars making use of the documents. She could also allow low sensitivity cooperation on, say, fishing and salvage operations with the mainland in the South China Sea. None of these steps have been taken by her predecessors. So she could make history.

The author is an honorary fellow at the Center of China-American Defense Relations, Academy of Military Science.