Seiji Maehara's decision Friday to resign as Democratic Party of Japan president will probably test the largest opposition party's solidarity and its conservative stance on defense, according to observers and DPJ sources.
Maehara has been one of the most conservative lawmakers in the DPJ on security policy.
He sparked debate in party by advocating revisions to the pacifist Constitution and calling China's growing military might a "a realistic concern," both reflections of views held by junior DPJ members who advocate more conservative defense policies and of its key foe, the ruling Liberal Democratic Party.