After cycling through seven leaders in seven years — many of whom squandered their support months, if not weeks, into their terms — Japan is about to break free from its most vexing political pattern. It's on the verge of stability.

Polls suggest that Sunday's House of Councilors election will provide an overwhelming victory to the ruling Liberal Democratic Party, handing right-wing Prime Minister Shinzo Abe a chance to become the nation's most transformative leader since the collapse of the bubble economy two decades ago.

Last December's election for the more powerful House of Representatives brought the LDP and Abe into power. But this election — for 121 of the 242 seats in the Upper House — will give the party a chance to claim majorities in both Diet chambers, breaking the long-standing "twisted legislature" that slowed down or blocked even modest policy proposals.