WASHINGTON Democratic Senators Arlen Specter and Blanche Lincoln will be fighting for political survival on Tuesday in contests that could test the depth of anti-Washington anger ahead of November's midterm elections.
On the biggest day of the campaign season so far, the two moderates face strong challenges from the left in their home states of Pennsylvania and Arkansas. In Kentucky, Republicans choose between an establishment favorite and a conservative "Tea Party" contender to run for an open Senate seat.
The three primary battles could turn on a growing wave of anti-establishment voter anger fueled by severe distrust of Washington and worries that neither party is doing enough on the economy, unemployment and to restrain government spending.
Prominent incumbents in each party -- three-term Republican Senator Robert Bennett of Utah and 14-term Democratic Representative Alan Mollohan of West Virginia -- already failed to win nomination in the past week in a possible sign of things to come.
"I haven't seen anything like it in 30 years. In both parties, it's out with the old and in with the new," said pollster Brad Coker of Mason-Dixon Polling and Research. "People are just angry with anything and anybody that has to do with Washington."
That anger could dent the traditional advantages in money and name recognition that have helped more than 94 percent of U.S. House of Representatives incumbents win re-election in the last decade. Senate incumbents fared nearly as well.
But the likelihood that this year could be different has fueled panic in some Washington circles ahead of a November election when 435 House seats, 36 Senate seats and 37 governorships are at stake.
"This is a year when being an incumbent is not the advantage it normally is, and in some cases it's a decided disadvantage," Quinnipiac University pollster Peter Brown said. "An anti-incumbent wave is building that we are just beginning to see."
Specter, a 30-year Senate veteran and former chairman of the Judiciary Committee, would become the biggest political name to go under that wave if he loses on Tuesday.
'SAVING ONE JOB: HIS'
He switched from Republican to Democrat last year after realizing he could not win a Republican primary, but a 20-point lead over Representative Joe Sestak has slipped to a dead heat as Sestak questioned Specter's party credentials.
Sestak has been airing a television ad with the tag line: "Arlen Specter switched parties to save one job -- his, not yours."
Party officials have rallied to Specter's aid, and he aired an ad featuring President Barack Obama praising him. But even with a primary victory, Specter would face a tough re-election fight in November against Republican Pat Toomey.
Toomey, a former congressman who unsuccessfully challenged Specter in the 2004 Republican Senate primary, has a slight lead over Specter in the latest Quinnipiac poll.
In Arkansas, two-term incumbent Lincoln is in a heated primary race with Lieutenant Governor Bill Halter that features nasty nicknames -- "Bailout Blanche" and "Dollar Bill Halter" -- and a grass-roots campaign for Halter by labor unions and activists.
Unions are unhappy with Lincoln's failure to support a bill making it easier to organize workplaces, while some activists are angry at Lincoln's opposition to a public insurance option in the healthcare overhaul.
During the debate on an overhaul of financial regulations, Lincoln introduced a tough bill to force investment banks to dump their derivatives businesses in what critics called an overture to the left.
Like Specter, Lincoln faces a tough general election campaign even if she beats Halter. Polls show Representative John Boozman, expected to emerge from a crowded Republican primary, currently leads her in a potential November matchup.
"At the end of the day, whoever wins that Democratic primary is probably going to lose the general election," Coker said.
For Republicans, Tuesday's highlight will be the Kentucky battle between establishment favorite Trey Grayson and Rand Paul, a doctor and son of libertarian Republican Representative Ron Paul, who has been backed by conservative "Tea Party" groups.
A victory for Paul, who leads in recent polls, would be another boost for a Tea Party movement that helped take down Bennett in Utah and drive moderate Governor Charlie Crist out of Florida's Republican Senate primary. Crist will run as an independent.
Grayson has been endorsed by Senate Republican leader Mitch McConnell of Kentucky, whose support in most years would clear the field of challengers. But Paul has been endorsed by Senator Jim DeMint of South Carolina, feeding speculation DeMint will challenge McConnell for his leadership post in December.
Pennsylvania also will hold a special House election to replace Democrat John Murtha, who died in February. A Republican win would be a first step in their climb toward reclaiming House control -- they need to gain 41 seats in the 435-seat chamber.
(Editing by Vicki Allen)