OSAKA — To lose one prime minister may be regarded as a misfortune; to lose two in one year looks like carelessness. That paraphrase by Oscar Wilde aptly sums up the current state of Japanese politics, given the serial resignations of Prime Ministers Shinzo Abe and Yasuo Fukuda.

Japan is once again saddled with a caretaker government as the ruling Liberal Democrat Party scrambles for a new leader ahead of elections for the Diet's Lower House. The question is: Who or what has been careless? The LDP? The Constitution? The voters?

For the last two years, the ruling LDP-Komeito coalition has dominated the powerful Lower House with a two-thirds majority. For a year, the opposition Democratic Party of Japan and other mini-parties have controlled the Upper House, which can veto legislation. Political instability and gridlock have been the inevitable result. The problem is that another election won't fix this political mess, but will likely only ensure continuing paralysis. Japan's political system requires the same sort of structural reform that its economy has long needed. And, as with the economy, its politicians don't appear ready to deliver anything that daring.