Adam B finds the relevant statute:

   AS 15.25.110. Filling Vacancies By Party Petition.

   If a candidate of a political party nominated at the primary election dies, withdraws, resigns, becomes disqualified from holding the office for which the candidate is nominated, or is certified as being incapacitated in the manner prescribed by this section after the primary election and 48 days or more before the general election, the vacancy may be filled by party petition. The central committee of any political party or any party district committee may certify as being incapacitated any candidate nominated by their respective party by presenting to the director a sworn statement made by a panel of three licensed physicians, not more than two of whom may be of the same political party, that the candidate is physically or mentally incapacitated to an extent that would in the panel's judgment prevent the candidate from active service during the term of office if elected. The director shall place the name of the person nominated by party petition on the general election ballot. The name of a candidate disqualified under this section may not appear on the general election ballot.

So Stevens can be replaced on the ballot assuming he pulls out of the race by September 17th. There's a primary before that, but it's unlikely any of the 2-3 other challengers will beat Stevens. The rest of the Alaska GOP is dirty, including Gov. Palin. So there's not really too many directions for the GOP to take here.

Now sounds like a great time to chip in to Mark Begich's efforts on the Road to 60.