It would be an understatement to say the Democratic Party, Japan's biggest opposition party, is struggling.

The DP has recently seen an exodus of 13 official candidates in the run-up to the Tokyo Metropolitan Assembly election. In a further blow, one influential member has quit the party's leadership and another has left the party itself.

The leading opposition party's support rate remains abysmally low at 6.7 percent, according to the latest NHK opinion poll.