Political transitions in East Asia promise to mark a defining moment in the region's jittery geopolitics. After the ascension in China of Xi Jinping, regarded by the People's Liberation Army (PLA) as its own man, Japan seems set to swing to the right in its impending election — an outcome likely to fuel nationalist passion on both sides of the Sino-Japanese rivalry.

Japan's expected rightward turn comes more than three years after voters put the left-leaning Democratic Party of Japan (DPJ) in power.

By contrast, South Korea's election — scheduled for Dec. 19, just three days after the Japanese go to the polls — could take that country to the left, after the nearly five-year rule of rightist President Lee Myung Bak, who proved to be a polarizing leader.