Okinawa’s governor election next month is set to be a major test of whether Japan’s ruling party can win over voters from a prefecture that has long opposed its security agenda and the heavy US military presence on its islands. A victory by Genta Koja, the Liberal Democratic Party-backed candidate, would likely help smooth ties between Okinawa and Tokyo and weaken resistance against the planned relocation of the US Marine Corps’ Futenma base within the prefecture, according to analysts. Such an...