Leading into Tuesday's primary, Alaska's gubernatorial campaigns have been largely overshadowed by hard-driving runs for a U.S. Senate seat and a ballot referendum to repeal the current version of the state's oil tax.

Expect the race for governor to fire up for the November general election.       

Republican incumbent Gov. Sean Parnell and Democratic challenger Byron Mallott only have token rivals in the primary and thus far have waged low-key campaigns. Each is expected to breeze through the primary, setting up a three-way race when independent candidate Bill Walker joins them on the November ballot.           

Political observers say Parnell holds an edge, not just as the incumbent, but because any anti-Parnell vote will be fractured between his competitors.          

Mallott's campaign and Walker disagree, saying their campaigns are picking up momentum.