WASHINGTON — The tea party movement's upset victory Tuesday by an insurgent conservative in Delaware's Republican Senate primary puts GOP chances to win control of the U.S. Senate in November in serious jeopardy.
They need to gain 10 seats to run the Senate. Most leading prognosticators had said they appeared to be within reach of that until Tuesday. (Although most analysts say Republicans still have a good chance to gain a majority in the House of Representatives, where they need to pick up 39 seats.)
Delaware's not the only Senate race in November where Republicans will field a tea party candidate vulnerable to the "fringe" label against well-known Democrats in the Nov. 2 general elections.
Colorado and Nevada face the same scenario, with incumbent Democrats seeking re-election against tea party insurgents who defeated better-known Republican candidates in low-turnout contests.
However, among the Senate seats most analysts expected Republicans to gain was Delaware's, where the GOP establishment's choice for Senate nominee was Rep. Michael Castle. A former two-term governor, the popular 71-year-old Castle has won 12 statewide elections and routinely pulls many Democratic and independent votes.
Running, however, in a closed Republican primary Tuesday in which Democrats and independents couldn't vote, Castle was upset by little-known tea party candidate Christine O'Donnell.
As of Sept. 1, Delaware has a total of 621,746 registered voters. Nearly half are registered Democrats, while another 146,000 are independents.
Despite the intense campaign in the small state, the GOP primary attracted only a 32 percent turnout Tuesday. That means that a passionate but relatively small tea party movement was able to win a majority of a light Republican turnout.
Next, however, O'Donnell must face Democrat Chris Coons in the Nov. 2 general election. He's the executive of New Castle County, the most populous of the state's three counties. O'Donnell pulled 30,561 votes Tuesday. In Delaware's 2006 general election, Democratic Sen. Tom Carper won — with 170,567 votes.
Closed primaries, where only registered party members can vote, tend to reflect the "small, intensely held preferences of fringe groups, and compared to the electorate in open races, the small size of the tea party makes it a fringe group," said Michael Munger, a political science professor at Duke University.
O'Donnell's victory makes Republican control of the Senate a "lost cause," Munger said "unless the depth of anti-Obama anger is bigger than anything we've seen."
In Colorado, Democratic Sen. Michael Bennet faces tea party-backed Ken Buck. The race is rated a toss-up.
In Nevada, polls show former State Assemblywoman Sharron Angle, the tea party insurgent Republican, deadlocked with Senate Majority Leader Harry Reid.
Still, Angle's tea party backing "could make the difference between her winning or losing," said Brad Coker, the managing director of Mason-Dixon Polling & Research, which polls in the state. Her tea party message could spark a higher turnout among Republicans and conservative-leaning independents, while Reid's falling popularity among Democrats and independents could leave him vulnerable, Coker said.
Alaska's Senate race is widely considered especially unpredictable. Incumbent Republican Lisa Murkowski was upset by tea party-backed Joe Miller. However, Murkowski is considering a write-in bid to make it a three-way race, so the outcome's difficult to gauge at this point.
Nevertheless, the tea party movement has a political problem: It has yet to demonstrate that it can extend its reach beyond candidates who often have trouble appealing to a broader constituency. It's also split the Republican Party.
"The Republican Party is a very divided party at this point," said House Majority Leader Steny Hoyer, D-Md.
Democratic National Committee Chairman Tim Kaine offered a bloody analogy of the GOP-tea party relationship.
"They invited the tea party in and it's turning into the Donner Party," Kaine said in a conference call with reporters, referring to American pioneers who were snowbound in the Sierra Nevadas in the 1840s and resorted to cannibalism to survive.
Republican leaders Wednesday officially got behind O'Donnell.
"Let there be no mistake: The National Republican Senatorial Committee — and I personally as the committee's chairman — strongly stand by all of our Republican nominees, including Christine O'Donnell in Delaware," said Sen. John Cornyn, R-Texas.
Other Republicans were wary. During the primary campaign, Delaware GOP officials tarred her as a con artist. Castle aides said he wouldn't endorse her anytime soon, if at all.
In light of all this, can Republicans pick up 10 Senate seats in November?
Polls show that four incumbent Democrats are locked in tight races for re-election — in Arkansas, Wisconsin, California and Washington.
New Democratic Senate candidates also face tough struggles to hold seats in five states where incumbent Democrats are leaving — Pennsylvania, Illinois, Connecticut, West Virginia and Indiana. That's nine Democratic seats in play; if the GOP claimed them all, they'd still be one short.
Republicans are expected to pick up the North Dakota seat now held by retiring Sen. Byron Dorgan, a Democrat. That could be 10.
However, Republicans face tight races to retain at least five seats they now hold — in Florida, Kentucky, Missouri, New Hampshire and Ohio. Lose any one and even a sweep of the endangered Democratic-held seats would leave the GOP short of Senate control.
Republicans warned Wednesday about getting too enthusiastic in states where Democrats have dominated, especially since many of their tea party candidates must kiss and make up with their local GOP establishment.
Sen. Lindsey Graham, R-S.C., said that Republicans shouldn't get overconfident about their prospects in November.
"Every month and every day is an election cycle of its own, and there's a long way to go. But we are doing well because they've (Democrats) sort of overreached," he said. "If you think that the Republican Party in and of itself has come back in good standing, that's not the message. The message is they want us to check the Democrats."
ON THE WEB:
MORE FROM MCCLATCHY:
For more McClatchy politics coverage visit Planet Washington