Just before he died, Governor Onaga announced that he would rescind his predecessor’s approval to use landfill in the construction of the runway, the latest in a series of legal maneuvers he used to thwart the base’s relocation.

Miwako Aragaki, a clerk at a grocery store in town, said she voted for Mr. Onaga four years ago because of his opposition to the new base and would vote for Mr. Tamaki this time.

During the campaign, American military officials are trying to remain “as invisible as we can humanly be,” said Lt. Gen. Eric M. Smith, the commander of the Third Marine Expeditionary Force on Okinawa.

In an interview in his office overlooking an expanse of ocean about 20 miles south of Henoko, General Smith said it would be up to Okinawa to negotiate with Tokyo over the location of any new bases.

“That is really an internal question for the government of Japan,” he said.

On the campaign trail, Mr. Sakima has steadfastly avoided talking directly about the American bases, focusing instead on the economy. At a campaign event in Yonabaru on the southern end of the island on Tuesday night, Mr. Sakima touted his work to reduce school lunch fees and medical costs as mayor of Ginowan.

Ryogo Okuhira, 31, a construction worker who attended the campaign event, said he liked Mr. Sakima’s focus on the economy and was skeptical that Mr. Tamaki would lure new businesses to Okinawa if he was preoccupied with the fate of the military base.

“Reality is more important than ideals,” Mr. Okuhira said.