Tuesday's crucial primary elections in Pennsylvania, Kentucky and Arkansas have drawn extraordinary attention from politicians and strategists in both parties who are eager to read an unsettled electorate.
But the results are not likely to offer a single satisfying answer to how big Democratic losses might be in November. Rather, Tuesday's voters will drop clues on a variety of questions, about anti-incumbent sentiment, "tea party" power and presidential popularity. Most attention remained focused on Sen. Arlen Specter (D-Pa.), who made a final appeal to voters in his new party Monday, asking them to extend his 30-year career in Washington. Rep. Joe Sestak (D-Pa.), Specter's challenger in the Senate primary, claimed momentum in the closing days of the campaign, and polls showed the race was too close to call.
Specter, who switched parties last year, has the backing of President Obama, Vice President Biden, Gov. Edward G. Rendell and much of the Democratic establishment. But Sestak has run an effective insurgent's campaign highlighted by a devastating ad that portrayed Specter as a political turncoat motivated to change parties only to save his job.
A Specter loss would be the third defeat for a congressional incumbent in less than two weeks and highlight anti-incumbent sentiment in the country confronting Democrats and Republicans -- although switchers often have trouble winning the allegiance of their new party's rank-and-file. Sen. Robert F. Bennett (R-Utah) and Rep. Alan B. Mollohan (D-W.Va.) have already been defeated.
Insiders in trouble
But the Specter-Sestak race is only one part of the political mosaic that will be examined after Tuesday's vote.
In Arkansas, Sen. Blanche Lincoln (D), who angered her party's base by flip-flopping on the "public option" during the health-care debate, was seeking to avoid a runoff against Lt. Gov. Bill Halter. Halter scheduled 20 stops in 25 hours in the hope of forcing that runoff that his supporters believe would give him a better opportunity to defeat the incumbent.
In Kentucky, Republicans waited to see whether Rand Paul -- an ophthalmologist, son of Rep. Ron Paul (R-Tex.) and favorite of the tea party movement -- could carry his outsider's campaign against Trey Grayson, the secretary of state.
Paul had a strong lead in polls. On Monday, Grayson showed the frustration of a candidate who might have thought he would have a relatively easy path to victory, with the endorsements of Senate Minority Leader Mitch McConnell (Ky.) and much of his state's GOP leaders. He said that Fox News Channel continually promoted his opponent and indirectly suggested that the network had more power within the party than the establishment itself.
The race that might hold the most clues to November, however, played out in rural southwestern Pennsylvania, where voters will fill the vacancy created by the death of Rep. John P. Murtha (D). Polls showed the race between Democrat Mark Critz, a former aide to Murtha, and Republican businessman Tim Burns to be a tossup.
The culturally conservative district is the only one in the nation that flipped from Democrat to Republican in the 2008 presidential race. And it is exactly the kind of area Republicans must win in November to take control of the House. Each of the national parties has poured more than $1 million into the district.
Primaries will also be held in Oregon on Tuesday.
Turnout a clue
One big question that could be answered is how strong outsiders' appeal is in a year in which dissatisfaction with Washington is broad and deep. Paul's campaign in Kentucky has been grounded in this message, and Sestak, too, has cast Specter as the ultimate insider. In the special election in Pennsylvania's 12th Congressional District, Burns has done the same to Democrat Critz, although he was only a congressional staffer.
Another answer that might emerge is how enthusiastic voters in the two parties are, measured in part by turnout. Special elections are not always reliable indicators of midterm outcomes, but if Democrats manage to hold onto the Murtha seat in Pennsylvania, strategists in both parties may be forced to recalibrate the GOP's prospects for taking control of the House in November.
Obama's appeal also will get a fresh look in the wake of Tuesday's results. Although he backed Specter, he did not stump for him in the final days of the campaign. Nor did he go into the special House election; instead it was former president Bill Clinton who was at Critz's side on Sunday.