CNN

Idaho Gov. C.L. "Butch" Otter stood behind his friend Sen. Larry Craig Saturday as Craig announced his intent to resign

WASHINGTON (CNN) - So Sen. Larry Craig says he intends to step down from his office as of September 30. The Republican from Idaho says he’ll resign amid a controversy over his arrest in June in a men’s restroom at the Minneapolis-St. Paul International Airport on suspicion of making sexual advances to an undercover police officer.

Craig said Saturday that he hopes “to allow a smooth and orderly transition of my local staff and for the person appointed to take my place.” The man who will appoint that successor, Idaho’s Republican governor, C.L. "Butch" Otter, stood behind Craig at the announcement in Boise.

Otter, a Republican, will almost certainly name a Republican to fill the seat, and that interim person will serve until next year’s election. That person will also most likely have a major edge in the 2008 contest.

And here’s why: Idaho is a very red state. As mentioned, the governor is a Republican, as is Craig and the other U.S. senator, Mike Crapo. Both U.S. representatives are Republican, and President Bush cruised to victory in Idaho in 2004, winning 69% of the vote.

So who will Otter pick to step in for Craig? Reports point towards Lt. Gov. Jim Risch. But Otter says such reports that he’s already decided on Risch are “just plain wrong.” And the governor says he’ll name a successor for Sen. Craig at his own pace.

Craig’s seat is up next year, and a number of Republicans were said to be interested in running if Craig had decided to retire after three terms. Besides Risch, the list includes Rep. Mike Simpson and possibly former governor and current Bush Administration Interior Secretary Dirk Kempthorne.

The leading Democratic challenger at this point appears to be former Congressman Larry LaRocco, who’s already actively campaigning, but has only raised around $80,000.

– CNN Deputy Political Director Paul Steinhauser