Photo/Becky Bohrer/AP

Alaska Lt. Gov. Mead Treadwell wants to unseat Alaska's Democratic Sen. Mark Begich in November.

But first, he needs to survive a tough GOP primary.

Treadwell, a figure in Alaskan politics for nearly 40 years, faces Dan Sullivan, a Marine and former Bush administration official, and Joe Miller, a Sarah Palin-supported tea party candidate who challenged Republican Sen. Lisa Murkowski in 2010.

The three-way race for the GOP nomination is not only the most expensive in Alaska's history -it's also considered to be one of the most negative, as the Republicans have attacked each other as well as the incumbent.

Democrats and Treadwell have attacked Sullivan, considered to be the Republican frontrunner, for lacking roots in Alaska. Critics say he's a carpetbagger, having moved to Alaska in 1997 and spending many years in Washington working for the Bush administration. Sullivan has responded by highlighting his wife's Alaska native background.

While Treadwell, 58, has been outspent by Sullivan and his supporters in the national GOP establishment, he remains optimistic heading into into the final stretch of a race still considered competitive.

Treadwell spoke with ABC News ahead of casting his own primary vote about Republican infighting, personal ties to Alaska and what it means to be endorsed by an astronaut. The following is a Q&A, edited for brevity.

How are you feeling about your chances on Election Day?

We can win this! Polls show us neck-and-neck with Mr. Sullivan, the favored candidate of the outside money interests. I want to be the favored candidate of Alaskans.

Did you expect the race to be this expensive?

I didn't expect the arrogance of certain national Republican Party folks to pick our candidate. I'd wish they'd save their resources for the fall. To have outsiders tell us who our senator should be doesn't go well here.

You've received money from out-of-state as well.

I certainly have, but 60 percent of our funding for what is a normal-sized Alaska campaign has come from inside Alaska. Over 90 percent of my opponent's funding has come from outside Alaska.

I just called my mom and said, 'You know Dan's parents just sent him $300,000.' My mom said, 'Well I'm on Social Security son, I can't really help you.'

But the kind of money we've raised has been sufficient to get our word out. One million dollars in Alaska is sufficient to run a statewide race and we've done that very well.

[Treadwell had $1.2 million in the bank compared to Sullivan's $4 million in late July, according to campaign filings.]

What about the negativity of the race?

I think Alaskans see through that, and we have worked very hard to contrast our record,which is not just time in the state, but making progress on things that have helped build this state.

Why does residency matter in this race?

For a lot Alaskans that's important because you're not just shoveling snow. It's important because to represent Alaska you need to know Alaska. That's a vulnerability the Sullivan campaign has addressed multiple times.

And the fact that they were doing "I'm not a carpetbagger" ads through late July, the fact that ads I saw this morning say his roots in Alaska go back 20 years, obviously that's a sensitive point with them.

You have been in Alaska for 40 years, but you were born in Connecticut.

I got here as fast as I could and I've never left. I don't think anybody could say I haven't worked on Alaska's issues.

I got elected lieutenant governor by the largest margin in state history. I'll put my record against Sullivan's any day.

Republicans have accused Democrats of 'meddling' in the primary with negative advertisements against Sullivan. Could they help deliver you the nomination?

Dan's response is to say the Democrats are trying to pick a candidate. I think they've helped him pass his name recognition issue, so that helped him a lot.

What they've spent is proportional to what Sullivan has brought in. He invited the snowball fight, that kind of money was not necessary in the primary.

Can the GOP recover and close ranks in the general election?

In six years, Mark Begich has voted with Obama 96 percent of the time. He has voted and put in legislation taking away power from the young state of Alaska and turned it over to the bureaucracy in Washington. He's done that with Obamacare, he's done that with the EPA.

All three Republican candidates are better than Mark Begich. I will support the Republican nominee.

You received an endorsement from astronaut Buzz Aldrin yesterday. You don't see that very often.

I've known Buzz. He's been a regular visitor to Alaska, and we've spent time on fishing boats together. When my wife died of cancer, he came up on his own to raise money to send 10,000 kids to a science center, so I was honored to have his endorsement, since he does not usually make them.

Buzz Aldrin wants us to go to Mars. Will you support that if elected to the Senate? What will you do for NASA?

I've always been impressed how Buzz has never rested on his laurels, and how he's always pushed for further travels. But I haven't taken a position on that. I believe that we are a space-faring nation, and a space-faring species.