Trey Grayson, Blanche Lincoln and Arlen Specter are battling in closely watched races. | AP photo composite by POLITICO Sestak, Paul score wins as Lincoln faces runoff

Upstart Senate candidates claimed two stunning victories in primary elections Tuesday night as Pennsylvania Rep. Joe Sestak denied incumbent Democrat Arlen Specter renomination to a sixth term and Kentucky insurgent Rand Paul easily bested establishment favorite Trey Grayson for the Republican Party's Senate nod.

In the evening's third key Senate race, Arkansas Sen. Blanche Lincoln clung to a slim lead of a few thousand votes over Lt. Gov. Bill Halter with nearly 85 percent of the vote counted in the state's Democratic primary, but will face an expensive and potentially dangerous June 8 runoff since neither candidate will reach 50 percent of the vote.


Insurgents didn't completely rule the night, however. Democrat Mark Critz, a former Hill aide, defeated Republican Tim Burns in the special election for the Pennsylvania congressional seat of the late Rep. John Murtha. Both parties invested millions in the race — viewed as a bellwether election for the fall campaign.

The AP called Pennsylvania's Senate primary for Sestak just before 10:15 p.m., as Sestak led Specter, 53 percent to 47 percent, with 65 percent of precincts reporting. The second-term congressman and former admiral will face off against former GOP Rep. Pat Toomey in the general election.

Addressing supporters shortly after the race was called in Sestak's favor, Specter endorsed his victorious opponent: "I will support him in the election."

With nearly all precincts reporting in Kentucky, Paul was drawing 59 percent of the vote to Grayson's 35 percent — a yawning lead over a candidate once viewed as a sure bet for his party's nomination and openly backed by Senate Minority Leader Mitch McConnell.

In his victory speech, Paul applauded the tea party movement and issued a stern warning to the political establishment: "I have a message, a message from the tea party, a message that is loud and clear and does not mince words: We've come to take our government back."

"The tea party movement is about saving the country from a mountain of debt that is devouring our country and that I think could lead to chaos," Paul said grimly, laying in to President Barack Obama for his participation in last year's Copenhagen summit on global warming and accusing Obama of trying to "apologize for the industrial revolution."

Reactions to Paul’s nomination split sharply from the left and right. Former Alaska Gov. Sarah Palin, who endorsed Paul in the primary, called the election a “wake-up call” in an interview with the Associated Press, describing the campaign as “an opportunity to not embrace the status quo but to shake things up.”

Democratic National Committee Chairman Tim Kaine painted the Kentucky race as a victory for “the far-right Republican segment of the electorate,” calling Paul a nominee “whose ideas are outside of the political mainstream.”

On the Democratic side in Kentucky, state Attorney General Jack Conway narrowly defeated Lt. Gov. Daniel Mongiardo, leading 44 percent to 43 percent, with 98 percent of precincts reporting, and giving national Democrats their preferred candidate for the fall campaign.

Though the White House and the Democratic Senatorial Campaign Committee strongly backed Specter in the Pennsylvania primary fight, the DSCC quickly released a statement responding warmly to Sestak's victory.

"Joe Sestak has a compelling life story and a powerful message of change. He knows what is wrong with Washington and, if elected to the Senate, will shake up how business is done in the Capitol," DSCC Chairman Robert Menendez (D-N.J.) said.

In state elections, Pennsylvania Attorney General Tom Corbett was nominated as the GOP's candidate for governor. The AP called the Democratic gubernatorial primary for Allegheny County Executive Dan Onorato before 10 p.m.

In Arkansas, Lincoln and Halter spent the last day of the campaign tamping down expectations.

“We certainly hope to win today outright, but I do think it’s fair to point out that when you’ve been in a race one week and you’re taking on an 11-year incumbent, who has been a member of Congress for four years before that, by anybody’s reckoning, a runoff would be a victory for us,” Halter told reporters.

Lincoln said she’d be “ecstatic one way or the other, whether we win right out or whether we go to a runoff.”

On the Republican side, Rep. John Boozman, the popular congressman from Northwest Arkansas, was able to avoid a runoff, easily disposing of Lincoln's 2004 opponent, Jim Holt, as well as state senator Gilbert Baker in a crowded eight-candidate field.

Even as voting got under way Tuesday morning, a pair of breaking political scandals added new fireworks to the already theatrical day.

The New York Times reported Monday night that Connecticut Attorney General Richard Blumenthal, running for the Senate as a Democrat, had repeatedly misrepresented his activities during the Vietnam War. Under fire for suggesting he had served overseas when he had not, Blumenthal called an emergency press conference at a VFW hall Tuesday afternoon to push back against the story.

At the hastily assembled afternoon event, where he was surrounded by veterans, Blumenthal struck a defiant note, declaring: "On a few occasions I have misspoken about my service and I regret that, and I take full responsibility. But I will not allow anyone to take a few misplaced words and impugn my record of service to our country." Blumenthal called his disputed remarks "absolutely unintentional, a few misplaced words — 'in,' instead of 'during,' totally unintentional."

New Jersey Sen. Robert Menendez, chairman of the Democratic Senatorial Campaign Committee, signaled his party would stand by Blumenthal as its candidate as Connecticut Democrats assemble this weekend for a nominating convention.

“I’m sure those veterans who will be standing up for him today will make the case for him, that he will continue to stay in the Senate race and that we will continue to support him,” Menendez said.

Meanwhile, a once-predictable House contest was upended by the resignation of Indiana Republican Rep. Mark Souder, who admitted to an extramarital affair with an aide in an emotional statement.

“I have sinned against God, my wife and my family. ... I am so shamed to have hurt those I love,” Souder said. “My family were more than willing to stand here with me. We are a committed family. But the error is mine, and I should bear the responsibility.”

It was not immediately clear who would replace Souder on the ballot in his Republican-heavy district. Souder won renomination earlier this month with less than 50 percent of the vote, against a split field of GOP challengers. The Democratic nominee is physician Tom Hayhurst.