The breakup of Ishin no To (Japan Innovation Party) now looks certain as its founder, Osaka Mayor Toru Hashimoto, has left the party and unveiled a plan to create a new national force with Osaka-based Ishin lawmakers close to him. In fact, the split of the No. 2 opposition party — an amalgam of lawmakers from a variety of political backgrounds who rallied around the popular mayor — seemed inevitable and long overdue, especially since Hashimoto announced his pending "retirement" from politics when his pet project for administrative reform of Osaka was voted down in a local referendum in May.

The next obvious question will be where the Ishin lawmakers are headed. Whether they stick around Hashimoto or pursue closer ties or even merge with the largest opposition group, the Democratic Party of Japan, they owe an explanation to voters — who by now may have grown tired of the repeated "realignment" of political forces.

What caused Hashimoto and his colleague, Osaka Gov. Ichiro Matsui, to bolt last week from the party that they effectively founded was Matsui's rebuke of Ishin secretary-general Mito Kakizawa's unilateral move to stump for a candidate in a Yamagata mayoral race who was supported by the DPJ and the Japanese Communist Party. Party chief Yorihisa Matsuno's rejection of the demand from Matsui, now an adviser, that Kakizawa quit from his post led the governor and Hashimoto, the supreme adviser, to leave Ishin.