Knowland's use of heavy-handed tactics to force Knight from the race, along with labor mobilization against Proposition 18, was a major factor in the Democratic landslide in California in 1958.

His seat was considered safe going into the 1958 midterm elections, but he stunned everyone when he announced his intention to run for governor instead of re-election to the Senate.

Knowland thought being governor would enhance his chances of challenging another Californian, Richard Nixon, for the 1960 Republican presidential nomination.

Brown steadily gained in the polls and defeated Knowland for governor, and Knight lost to Congressman Clair Engle in the Senate race.

Brown's landslide victory ended many streaks of Republican dominance in various counties throughout the state.