The Philippines should understand the ruling, which has cost the country tens of millions of US dollars, is nothing but a worthless piece of paper.

Any suggestion that China should accept the arbitration ruling first then negotiate will run into a stonewall because it is in direct contradiction to China's stance of neither participating in, nor accepting the arbitration, and neither recognizing, nor honoring the ruling.

Hence, if Manila truly wants to improve ties with Beijing, the Duterte administration needs to cast aside any illusions it may have over leveraging the arbitration ruling against China and show both sincerity and consistency in starting direct talks with China, which is the only viable way to resolve the disputes between them.

The Philippine leader also needs to understand his penchant for changing his tone on the South China Sea issue does a disservice to his efforts to improve ties with China.

True, Duterte backpedaled from his hardline rhetoric on China even before his inauguration as Philippine president, and after the ruling was announced, he went further to back direct talks with China. But he was also the one who said he had no plans to negotiate with China over the maritime disputes when meeting a US congressional delegation on July 20 in Manila.

The Philippine leader may use caprice as a tactic to test China's bottom line, but as a politician known for his pragmatism, he should let pragmatism prevail and continue to create the right conditions for resolving the South China Sea disputes with China in a peaceful way.

The author is deputy editor-in-chief of China Daily Asia Pacific. jasmine@chinadailyhk.com