Sen. Daniel Akaka’s retirement announcement Wednesday instantly opens the Democratic seat to a challenge from the GOP, and Roll Call Politics has moved the Hawaii Senate race rating from Likely Democratic to the more competitive category of Leans Democratic.

The dynamics of the race will depend largely on whether Republicans get their top-tier recruit, Linda Lingle. The former two-term governor was considering running before Akaka said he would not seek re-election and could have given him trouble with her proven fundraising ability, high name identification and support from a national party aiming for the Senate majority.

Lingle’s prospects increase greatly with Akaka out of the race, but without her, Republicans will have a difficult time in the state President Barack Obama grew up in. Obama, of course, will be on the ticket in 2012, and after winning there with 72 percent in 2008, the eventual Democratic nominee is all but assured of gaining some coattail assistance.

The Honolulu Star-Advertiser reported six Democrats as the most obvious possibilities to run for Akaka’s seat: Reps. Colleen Hanabusa and Mazie Hirono, Lt. Gov. Brian Schatz, Gov. Neil Abercrombie, former Honolulu Mayor Mufi Hannemann and former Rep. Ed Case. However, Abercrombie has said his current gig will be his last public office.

The Democratic Senatorial Campaign Committee, which now must defend five open seats in 2012, expressed confidence despite Akaka’s exit.

“He will be missed, but Democrats will absolutely keep his seat,” DSCC Chairwoman Patty Murray (Wash.) said in a statement. “With a heavily-leaning Democratic electorate and their native son up for re-election as President of the United States, we are confident the people of Hawaii will continue to have two Democrats serving them in the United States Senate.”

But with each retirement, the National Republican Senatorial Committee steps that much further into position for control of the Senate. (They only need to flip four seats to seize power.)

“The retirement of yet another longtime Democrat Senator further expands the map of takeover opportunities and further strengthens Republican hopes for a new Senate majority in 2012,” NRSC spokesman Brian Walsh said in a statement. “With several strong candidates already looking at this race, even before Senator Akaka’s announcement, Hawaii presents an unexpected opportunity for Senate Republicans and we intend to make the most of it in 2012.”

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