Prime Minister Shinzo Abe has thrown out the political playbook. With two years remaining in his term, and with his Liberal Democratic Party enjoying comfortable majorities in the Diet's upper and lower houses, Abe has called a snap general election for December.

Political leaders and pundits worldwide are scratching their heads at Abe's decision to risk his extensive reform agenda with a throw of the electoral dice. But while Abe may be known for his boldness, he is no reckless gambler. On the contrary, he would have been reckless to launch the third "arrow" of his so-called Abenomics strategy for reviving Japan's economy — supply-side structural reforms — without a clear mandate for reform.

Fortunately, Abe is almost certain to receive that mandate — not least because he lacks credible opponents. The main opposition party, the Democratic Party of Japan, essentially imploded following its previous turn in government, which was characterized by economic malaise and foreign-policy blunders. And Japan's other political parties have done nothing to convince voters that they deserve to emerge from the political wilderness.