Tsai Ing-wen, chairwoman of the Democratic Progressive Party in Taiwan, who will lead the island over the next four years, resorted to rhetorical ambiguity in Friday's inauguration speech.

Tsai is yet to give a forthright answer on the 1992 Consensus that both the mainland and Taiwan belong to one China, which has served as the political foundation for the peaceful development of cross-Straits relations. Instead, she said in her speech that she "respected" the fact that "several political agreements were reached by both sides in 1992", but stopped short of mentioning the 1992 Consensus.

However, she said she wants to prolong the peaceful exchanges that have been established, and promised that the island will be "a staunch peacekeeper" in regional security affairs, in which cross-Straits ties serve as a "key link". And Tsai did pledge to address cross-Straits affairs in line with the "Regulations on Relations between People in the Taiwan and Mainland Areas" and other relevant laws.

Yet, as a statement issued by the mainland after Tsai's inauguration speech said, "Taiwan independence" remains the biggest menace to peaceful ties, because Tsai failed to touch upon the nature of the cross-Straits relations, let alone the prospect of some DPP secessionists attacking the one-China principle.

The truth is, just like the Cairo Declaration signed by the heads of the governments of China, the United States and the United Kingdom in 1943, which justified the return of Taiwan to China and the postwar order in Asia-Pacific region, the 1992 Consensus is the fundamental agreement between the two sides of the Straits.

The worst-case scenario would be Tsai attempting to continue trying to muddle through without endorsing the Consensus completely or even denying it completely. Should that happen, the mainland will have to prepare for and deter the DPP's future moves to seek "independence".

It is also noteworthy that Taiwan has been invited to attend the Geneva-based World Health Assembly as an observer just three days after Tsai's inauguration, in accordance with the one-China principle reflected in the UN General Assembly Resolution 2758 and WHA Resolution 25.1.

As a special arrangement since 2009, the island's participation in the WHA will reveal a lot about whether the DPP will acknowledge the reality there is only one China. The WHA's belated invitation, which stresses that the DPP will be taking part in the event based on the one-China principle, enshrines the principle in Taiwan's political participation in international affairs.

If the Taiwan health authorities seek to challenge this in Geneva, insisting that the WHA's reiteration of the one-China principle has something to do with the mainland's "interference", the special arrangement is unlikely to last.

Worse, it might add more political uncertainties to cross-Straits relations, which the Kuomintang painstakingly steered in the right direction over the past eight years. Tsai should relinquish her delusional thinking that the mainland will sit idle while her party tries to tear China apart, bit by bit. The only option left for her is facing up to the 1992 Consensus.

The author is a professor at the Institute of Taiwan Studies of Beijing Union University.