The persistent clashing between the Abe administration and Okinawa Governor Takeshi Onaga over the relocation of a major U.S. military base claimed a high-level political victim in the July 10 Upper House election.

Exit polls showed Aiko Shimajiri, state minister for Okinawa and Northern Territories Affairs, going down to defeat to a candidate backed by four opposition parties in the Okinawa prefectural district.

It is rare for a sitting Cabinet minister to be ousted at the polls, and the defeat of Shimajiri adds another hurdle to efforts by Prime Minister Shinzo Abe and his Cabinet to relocate U.S. Marine Corps Air Station Futenma from Ginowan in central Okinawa Prefecture to the Henoko district of Nago, also in Okinawa.

With a Cabinet minister seeking re-election in Okinawa, the Abe administration placed priority on retaining the seat and sent high-ranking officials of the ruling Liberal Democratic Party to campaign on Shimajiri's behalf. However, those efforts were not enough to overcome the early and concerted cooperative support by the opposition parties for Yoichi Iha, a former Ginowan mayor, who ran as an independent.

Helping Iha's cause was the anti-U.S. military base sentiment in Okinawa that heightened before the official start of election campaigning with the slaying of a 20-year-old Uruma woman. A former U.S. Marine who worked as a civilian at Kadena Air Base is charged with her rape and murder.

The defeat of a Cabinet minister will give Onaga and his anti-base allies added momentum as they pressure the Abe administration to relocate Futenma outside the southern prefecture.

Shimajiri's defeat means the LDP has no Diet member representing Okinawa Prefecture.

Meanwhile, a second LDP Cabinet minister also fell to defeat as Justice Minister Mitsuhide Iwaki lost a close race in Fukushima Prefecture to Teruhiko Mashiko, an Upper House member from the opposition Democratic Party, who was also supported by the other opposition parties.

Frustration at the slow pace of recovery following the 2011 accident at the Fukushima No. 1 nuclear power plant may have been a key reason behind Iwaki's defeat.