Washington (AP) - With frustrated voters poised to punish the party in power, Senate Majority Leader Harry Reid and Sen. Barbara Boxer will find out their Republican opponents this fall. Fellow Democratic Sen. Blanche Lincoln will learn whether she'll even be on the November ballot.
Their states -- Nevada, California and Arkansas -- are among 12 holding primaries and runoffs Tuesday, the busiest night thus far of this year's congressional and gubernatorial elections.
Voters are choosing Democratic and Republican nominees for governor in several states like Iowa, where the general election contest was certain to be competitive. GOP primary voters in South Carolina are settling a nasty four-way contest.
The outcomes will determine matchups for November, when Democrats will try to maintain their comfortable majorities in the House and Senate and overcome Republican challenges in dozens of gubernatorial races.
Historically, the party that controls the White House takes a beating in the president's first midterm elections.
Still, neither party is safe from voters' ire.
Nationwide, Democrats and Republicans alike are facing an electorate angry over the state of the country, from the persistent economic woes to the typical ways of Washington. And earlier primaries indicated that voters are willing to fire Washington incumbents -- regardless of party.
The centrist Lincoln, a two-term senator, may be next.
She's in a runoff against Arkansas Lt. Gov. Bill Halter, who is being supported by labor unions and liberal groups that have spent millions to try to unseat the White House-backed senator. They were forced into a runoff for the party nomination after neither captured 50 percent of the vote in the May 18 primary.
The anti-incumbent mood also has put the vulnerable Reid of Nevada and Boxer of California on notice that they'll face tough re-election fights regardless of whom Republicans nominate.
In Nevada, three Republicans sought the chance to take on Reid and tea party darling Sharron Angle had an edge in final polling. In California, former Hewlett-Packard chief executive Carly Fiorina was leading the three-candidate field for the chance to challenge Boxer.
California also hosts a marquee GOP primary in the race to succeed term-limited GOP Gov. Arnold Schwarzenegger. Republican billionaire Meg Whitman, a former eBay chief executive who has spent more than $70 million of her own fortune, faced state insurance commissioner Steve Poizner, a wealthy former businessman. Attorney General Jerry Brown, a former governor, is the likely Democratic nominee.
Also, Republicans appear ready to oust Nevada Gov. Jim Gibbons in the wake of his messy divorce; former federal judge Brian Sandoval is favored for the GOP nomination.
Elsewhere, South Carolina Republicans are choosing a successor for the term-limited and scandal-scarred GOP Gov. Mark Sanford, and the victor probably will become governor of the heavily Republican state. State Rep. Nikki Haley had the advantage in the final days; she is trying to become the state's first female governor and overcome allegations of infidelity, which she denies.
Three Republicans in Iowa are battling for the right to oppose Democrat Chet Culver, considered one of the nation's most vulnerable governors.
Nevada, California and Arkansas are among 12 states holding primaries and runoffs Tuesday, the busiest days thus far of this year's congressional and gubernatorial elections.