Edward Teller of FireDogLake suggests a right-wing primary challenge could topple Lisa Murkowski in Alaska and nominate a Tea Party candidate instead:
U.S. Senate candidate, Sitka Alaska’s progressive mayor, Democrat Scott McAdams, trails U.S. Senator Lisa Murkowski in polls. But Sarah Palin has endorsed Murkowski’s challenger, Tea Party Express favorite Joe Miller in the August 24th GOP primary. Palin has a lot of prestige riding on being able to pull off this win.
I haven't seen any polling, and Teller's argument needs to be viewed with some skepticism since he's hyping the candidacy of Democratit Scott McAdams. Still, it doesn't seem crazy to imagine that a strong Democrat could beat a far-right Republican in Alaska, even in 2010.