The passage of a controversial land bill earlier in the year, as opposed to a compromise bill worked out by fellow Senator Ted Stevens that failed thanks to Gravel two years earlier, further harmed his reelection bid. A group of Democrats, including future governor Steve Cowper, campaigned against Gravel on the land bill issue.
Gravel's campaign funds, some of which came from political action committees outside the state, also became an issue in the contest. Another factor may have been Alaska's blanket primary system, which allowed unlimited cross-over voting across parties and from its large unaffiliated electorate; Republicans believed Gruening would be an easier candidate to defeat in the general election. The blanket primary had first been used in the 1968 election, and was something Gravel himself was able to capitalize on that year.
Gravel later said that by the time of his primary defeat, he had alienated "almost every constituency in Alaska." In the August 26 primary Gruening defeated Gravel by 11 percentage points.