The Democratic Party for the People approved Wednesday a proposal to merge with the Constitutional Democratic Party of Japan, a hard-fought achievement forming a more organized, numerically viable opposition force to counter Prime Minister Shinzo Abe.

In a general meeting held at a hotel in Tokyo, a majority of DPP lawmakers backed an agreement by secretary generals of both parties that would establish a new party and set its basic platform, manifesto and rules on electing its new leadership.

The agreement represents a repudiation of DPP leader Yuichiro Tamaki, who abruptly announced last week that he intended to divide up the party instead of unilaterally joining forces with the CDP. Tamaki has been seen as an obstacle — even by some members of his own party — to efforts to unite the two parties to create a new, merged party.