Here's why Tsai must endorse 1992 Consensus
Following Ma Ying-jeou's election in 2008, Taiwan endorsed the 1992 Consensus. Under this arrangement, both Taiwan and the Chinese mainland accept the principle of "one China", but each side holds its own interpretation of what that means.
By doing so, Ma enabled cross-Straits relations to move forward. Negotiations between Taiwan's Straits Exchange Foundation and the mainland's Association for Relations Across the Taiwan Straits re-opened for the first time in more than a decade. By 2016, senior cross-Straits officials from the two sides had met seven times and a total of 23 cross-Straits agreements had been signed. The number of direct cross-Straits flights soared from zero to 120 per day. Millions of mainland tourists visited Taiwan. And the mainland is now the island's largest trading partner.
International observers praised the progress in cross-Straits relations. Support for the rapprochement was even enshrined in the 2010 National Security Strategy of the United States. Even US President Barack Obama declared:"I am very pleased with the reduction of tensions and the improvement in cross-Straits relations."