Updated: 3:34 a.m.

With 51 percent of precincts reporting in the Alaska Republican Senate primary, lawyer Joe Miller led Sen. Lisa Murkowski by a slim margin of 52 percent to 48 percent.

Murkowski was heavily favored heading into Tuesday, and a loss would be the biggest surprise yet of the already unpredictable 2010 election cycle.

On Miller’s side were endorsements from former Arkansas Gov. Mike Huckabee and Alaska’s own former Gov. Sarah Palin, who defeated Murkowski’s father, then-Gov. Frank Murkowski, in the 2006 Republican gubernatorial primary.

Murkowski was appointed to the Senate by her father in 2002, and two years later she won a close election to a full term. The winner of Tuesday’s primary will be the favorite to win in November.