Cooperation between the Kuomintang and the Taiwan People's Party in the Zhubei mayoral election has formally broken down — bad news for both parties' supporters, and an unexpected gift for the Democratic Progressive Party.

• Huang Kuo-chang accused the KMT of breaking the agreement, ending the earlier understanding that the TPP would back Hsu Hsin-ying for county magistrate while the KMT ceded the mayoral race to the TPP.
• KMT candidate Wu Hsu-chih has already picked up his registration papers, saying party headquarters never asked him to withdraw; the TPP's Chiu Chen-yuan is not backing down either.
• The blue camp has not sorted out its own house, either: the rift between Hsu Hsin-ying and Chen Chien-hsien from the Hsinchu County magistrate primary has yet to be mended.
• Analysts believe that if the opposition parties remain divided, they could lose in both Hsinchu County and Zhubei at once, squandering what had been a highly favourable position.
• Disaffected supporters' votes could spill over, becoming the first domino to topple the 2026 local elections and even affecting opposition cooperation in 2028.

Outlook: Both parties still publicly invoke their "original intention to cooperate," but with the registration deadline approaching, separate candidacies are all but certain, and the odds are rising for DPP candidate Tseng Sheng-kai.