For weeks, Taiwan’s two main opposition parties were edging toward a coalition, in a bid to unseat the island democracy’s governing party in the coming presidential election, an outcome that Beijing would welcome. The election, one elder statesman from Taiwan’s opposition said, was a choice between war and peace.

This week, however, the two parties — which both argue that they are better able to ensure peace with China — chose in spectacular fashion to go to war against each other. An incipient deal for a joint presidential ticket between the long-established Kuomintang (KMT) and the upstart Taiwan People’s Party unraveled with the speed, melodrama and lingering vitriol of a celebrity wedding gone wrong.

A meeting that was opened to journalists on Thursday seemed to have been meant as a show of goodwill within the opposition. But it featured sniping between rival spokespeople, a long-winded tribute to the spirit of Thanksgiving by Terry Gou — a magnate turned politician trying to cajole the opposition toward unity — and mutual accusations of bad faith between the two presidential candidates who had been trying to strike a deal: Hou Yu-ih of the KMT and Ko Wen-je, the founder of the Taiwan People’s Party.