The mixed response to Lee Teng-hui's death on Thursday speaks volumes of how controversial a figure was the former Taiwan leader, whose political career was characterized by subterfuge, stratagem and sabotage.

Even those eulogizing him as "the father of Taiwan democracy" cannot deny the maleficent legacy he leaves behind, and the tensions he created across the Taiwan Straits, for instance, by pursuing separatism after becoming the leader of the island in 1996. By adopting separatist policies in the four years that followed, Lee poisoned cross-Straits relations.

Exhibiting the vision and foresight required of a person in his position was never part of his playbook, for he was determined to manipulate Taiwan compatriots' views by selling them secessionism in the garb of "democracy". It was during his tenure that the legal, political and institutional foundations of secessionism were laid on the island.

While betraying the cause of national reunification bequeathed to him by his predecessor Chiang Ching-kuo, he surrendered the command of the island to the United States. No wonder US Secretary of State Mike Pompeo, who is leading the anti-China campaign from the front, praised Lee to the skies for playing "a crucial role" in transforming the island into a "beacon of democracy" in a statement on Thursday.

Lee's brazen embrace of secessionism compelled Kuomintang, which adheres to the one-China principle, to expel him from the party in 2000 after he exited office and founded the pro-independence Taiwan Solidarity Union. And his open support to the pro-independence Democratic Progressive Party, the current ruling party on the island, exposed him as a manipulator of democracy and die-hard secessionist.

Despite Lee's ploy to fool people with his deceptive politics, it was clear even in the 1990s that his so-called Taiwan democracy agenda was, in fact, a secessionist conspiracy. Were it not for his separatist policies, the two sides of the Taiwan Straits would have maintained the momentum of exchanges that had gathered pace in the 1980s.

The legal and political institutions Lee established encouraged the secessionist forces on the island to grab power, and intensify the de-Sinicization process he began in the cultural and social spheres.

The beguiling politician, whom the US and Taiwan separatists portray as a sanctimonious leader, has dealt a grave blow to cross-Straits relations by opening a Pandora's box of faux democracy, deceit, distorted nationalism and secessionist doctrines. His attempt to turn the wheel of national reunification can only be described as an act of sabotage against the historical cause.

Yet despite his betrayal to the Chinese nation, there is no stopping the historical trend of national reunification and national rejuvenation.