Primary voters on Oahu could decide the fate of the city’s $5.26 billion rail project.

While rail will not be on the ballot on Aug. 11, the three leading candidates for mayor have competing visions for the project.

Mayor Peter Carlisle would continue with rail if re-elected to a second term. Former acting Mayor Kirk Caldwell would continue the project but could seek adjustments of station locations, architecture and visual effects. Former Gov. Ben Cayetano would attempt to stop the project and focus on improving the city’s bus system and other infrastructure.

Oahu voters approved the steel-on-steel design for the 20-mile rail line in November 2008, but the mayoral election could determine whether the project, which has already broken ground in Kapolei, actually gets built.

The mayor’s race could be decided in the primary if one of the candidates wins more than 50 percent of votes. If not, the two candidates who receive the most voters will face each other in the November general election.

On Hawaii island, voters will decide whether to elect Mayor Billy Kenoi to a second term. Former Mayor Harry Kim and Hawaii County Councilman Dominic Yagong are challenging Kenoi.

Statewide, U.S. Rep. Mazie Hirono and former U.S. Rep. Ed Case are vying in the Democratic primary to replace retiring U.S. Sen. Daniel Akaka, D-Hawaii. Hirono, a liberal, believes she better reflects the party’s values and would protect federal programs such as Social Security and Medicare. Case, a moderate, wants to take a middle path to end partisan gridlock and address federal budget challenges.

Former Gov. Linda Lingle, the leading Republican candidate for U.S. Senate, is expected to win the GOP primary and take on either Hirono or Case in November.

In the Democratic primary in the 2nd Congressional District, which covers rural Oahu and the neighbor islands, former Honolulu Mayor Mufi Hannemann and City Councilwoman Tulsi Gabbard are the leading candidates to replace Hirono.

All state House and Senate lawmakers are up for election this year under new political boundaries drawn after the results of the 2010 census. Democrats hold a 24-1 majority in the Senate and a 43-8 advantage in the House.

Economic recovery, environmental protection and improving education will likely be the issues that dominate the campaigns for state Legislature.