In a move that has the potential to affect Alaska’s U.S. Senate race, Mark Fish filed on Wednesday with the Alaska Division of Elections to run for the U.S. Senate seat as a Libertarian.

Fish has long been a Libertarian, and is well known in those circles, but worked as both a Sarah Palin and GOP Senate candidate Joe Miller staffer and remains close to the Miller campaign.

There’s been speculation that Fish is running in order to save a spot on the ticket for Miller were Miller to lose the Republican primary and chose to run as a Libertarian. It would be a move that would all but ensure a win for U.S. Sen. Mark Begich. However, in an interview, Fish said that he has never talked with Miller about that scenario.

“We’ve had conversations about a lot of things, but never about that,” Fish said.

He said that he is running so that Libertarians have a viable candidate to vote for in an open primary. The Republican primary has a closed ballot, meaning that those in other parties don’t get to vote for their candidate. The Democratic primary, however, allows for other parties.

“I want to give the registered Libertarians and people who choose an open ballot a choice other than Begich,” he said. After the primary, he said that he’ll reassess the situation. If he does stay in the race, he’ll likely draw away from the Republican candidate.

Anchorage-based Republican pollster and consultant Marc Hellenthal said that Fish would likely pick up about 5 percentage points if he stays in the race past the primary. “That could easily cost the Republican nominee the vote,” he said.

Another libertarian, Thom Walker, has filed to run for the seat, but Walker is an unknown and until recently was a registered Republican and has not been involved in the Libertarian Party. Numerous people, including this reporter, have tried to contact him in the last days but he can’t be reached.

“He’s not a viable candidate if he can’t answer his phone,” said Libertarian Party Chair Mike Chambers.

Fish is a longtime Alaskan. He spent 20 years in the National Guard. He ran for Anchorage Assembly in 2003 and for state House in 2008. He spent five years on the Human Rights Commission, until a controversial comment that he wrote on a blog about a “radical feminist” was unearthed.

Fish and Miller agree on more things than they disagree on, said Fish. However, Miller is “much more socially conservative than I am,” he said.

For instance, Fish, unlike Miller, doesn’t believe that the state should be involved in marriage at all. And also believes that abortion should be a societal, rather than legal decision.

GOP candidate Dan Sullivan’s campaign declined comment. Mead Treadwell and Joe Miller’s spokespeople didn’t return calls requesting comment.

Contact Amanda Coyne at amandamcoyne@yahoo.com