Why did opposition to a consumption tax increase weaken the Democratic Party of Japan in 2012?

The Democratic Party of Japan (DPJ) faced significant weakening in 2012 primarily due to Prime Minister Noda Yoshihiko’s decision to prioritize and successfully pass an increase in the national consumption tax.123

This legislative push had two major negative impacts on the party:

• Internal Fragmentation: The tax increase completely alienated Ozawa Ichirō, a powerful figure within the party. Ozawa was strongly opposed to the tax hike and subsequently resigned from the DPJ, taking dozens of members of his faction with him to form a new political party.13
• Public Discontent: The legislation, alongside Noda’s decisions to restart nuclear power plants and consider a trans-Pacific trade pact, fueled growing public dissatisfaction.23

This internal division and loss of public support left the DPJ vulnerable to pressure from the Liberal-Democratic Party (LDP). When Noda was forced to dissolve the lower house in November 2012, the DPJ suffered a landslide defeat in the subsequent December elections, with its seat count in the chamber dropping to 57.123