"The vote of this senator is not for sale and neither is the vote of the people of Arkansas," Lincoln said in her victory speech, rebuking national labor groups.
Lincoln had been blasted by national labor unions for voting for the federal bank bailout and opposing the option of a government-run insurance plan in the health care bill and the Employee Free Choice Act, or card check, a high priority for the labor movement.
She will face an even fiercer fight in November as Republicans take aim at her Senate record and take advantage of the anti-incumbent sentiment that has ended careers of Sen. Arlen Specter, D-Pa., and Sen. Bob Bennett, R-Utah.
Other key races Tuesday pitted party members against each other, marking the latest test for ideological movements within both major parties.
Tea Party supporters nabbed a victory in the contested runoff in Georgia, where former state representative Tom Graves defeated former state House member Lee Hawkins in a special election for the U.S. House of Representatives. Graves was backed by the Atlanta Tea Party Patriots and the conservative Club for Growth.
In another key battleground -- Virginia's fifth Congressional district -- the Republican establishment's candidate Robert Hurt flew to an easy victory with 48.4 percent of the votes.
Ex-Hewlett Packard chief executive Carly Fiorina defeated Rep. Tom Campbell and state Assemblyman Chuck DeVore in the race to challenge incumbent Democratic Sen. Barbara Boxer in November.
Fiorina, as with Haley in South Carolina, received an unexpected endorsement from Palin even though DeVore has been supported by Tea Party groups.
Palin had recorded a telephone message for Fiorina, urging voters to "help get our country back on track" by voting for the former executive.
Fiorina spent a lot of her own personal wealth on the campaign, a point likely to be seized upon by Democrats in the campaign for November. But Fiorina and Republicans are likely to emphasize the nation's anti-incumbent sentiment in their attacks on Boxer, who has served in the Senate for 17 years.
Former eBay chief executive Meg Whitman beat state insurance commissioner Steve Poizner for the nomination to succeed Gov. Arnold Schwarzenegger, the moderate Republican governor whose tumultuous time in office is coming to an end.
Whitman spent more than $70 million of her money in her campaign to succeed Schwarzenegger, a moderate Republican. She will face Democrat Jerry Brown, the state's attorney general who was governor from 1975 to 1983, in the fall.
Also on Tuesday, California voters approved a ballot initiative that could make the completed primary election the last to be held in the state.
Proposition 14 would replace party primaries with a "top-two" election structure for congressional, statewide and state legislative elections. All candidates would be included in a single primary election open to all voters, regardless of party registration. Candidates would have the option to declare a party preference or appear on the ballot with no affiliation.