Hawaiians head to the polls for bitter primary battle

[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2010/images/09/17/art.hawaii.sunset.jpg caption ="Saturday is primary day in Hawaii, the last in the country."]

(CNN) - After eight years in Republican hands, Hawaii Democrats hope to re-capture the governorship, but first they need to survive a bitter primary.

Saturday voters in the state head to the polls to cast ballots, and the hottest contest appears to be the Democratic gubernatorial battle. Former 11-term Rep. Neil Abercrombie is facing off with former Honolulu Mayor Mufi Hannemann in what's turned into a nasty race. The two candidates have a rivalry that dates back more than two decades.

Whoever comes out on top in the Democratic primary is expected to be the favorite in the general election against Lt. Gov. Duke Aiona, the presumptive GOP nominee. The winner in November will succeed term-limited Gov. Linda Lingle, who eight years ago became the first Republican governor of Hawaii in four decades. Democrats dominate elections in the state and President Barack Obama, who grew up in the state, captured 72 percent of the vote in Hawaii in the 2008 presidential election.

"Republicans are hoping that the competitive Democratic primary results in a bruised nominee and divided party that allows Aiona the chance to come out on top. It's possible, but the lieutenant governor still starts the general election as the underdog," says Nathan Gonzales, political editor of the non-partisan Rothenberg Political Report.

Democrats also hope to recapture Abercrombie's old House seat. He stepped down earlier this year to concentrate full time on his gubernatorial bid and Republican Charles Djou won the May special election to fill the remaining months of Abercrombie's when he faced two Democratic candidates split their party's vote. Only one of those two candidates, Democratic state Senate President Colleen Hanabusa, is expected to be on the ballot in November, as the other candidate, former Rep. Ed Case is not running again. Both Djou and Hanabusa are considered the overwhelming favorites in their party primaries and are expected to face off in November.

"No competitive primary is good news for Hanabusa and the Democrats. They're going to get the one-on-one match-up against Djou in November that they wanted in the special but didn't get. But it's still going to be difficult to oust the new congressman in November. It's Hawaii but it's not a lock for a Democratic pickup," adds Gonzales.

Saturday's contests in Hawaii bring an end to the primary season, which this year kicked off with the Illinois contests in early February.

Follow Paul Steinhauser on Twitter: @psteinhausercnn