By Alex Irwin

PoliticsPA contributor

 With just 11 days until the election, most expected Pennsylvania’s state-wide races to tighten up, especially in the battle for the U.S. Senate. But after some numbers released this week showed Democratic candidate Joe Sestak leading Republican hopeful Pat Toomey for the first time, no one’s exactly clear on how the race changed so quickly.

Last week, two polls sponsored by Democrats showed Sestak gaining ground. But this week, three separate Senate race polls showed Sestak with small leads, all within each polls’ margin of error. A report from left-leaning Public Policy Polling that came out on Tuesday put Sestak over Toomey by one point, 46 percent to 45 percent. A Quinnipiac poll released yesterday put him up 48 percent to 46 percent. A Morning Call/Muhlenberg College poll released Wednesday found Sestak up by three points with 44 percent of the vote over Toomey’s 41 percent. Tracking numbers by the Morning Call/Muhlenberg College released yesterday put the candidates at a tie, each with 43 percent.

The fact that independent polls also show the race is tightening in its final weeks doesn’t come as a major surprise, but Terry Madonna, a pollster for Franklin & Marshall College, said such an abrupt change in the numbers is somewhat unexpected.

“Typically you have waves, like a slow decline and a slow rise. This is a very dramatic change in a week or 10 days. This is pretty stunning, and getting a handle on exactly why it’s happened is what we’re all attempting to do,” Madonna said.

Madonna said races always tighten as more undecided voters begin to break in favor of a particular candidate, but he also credited the Democrats’ efforts to spur voter enthusiasm. Whether or not Democrats will bring enough people to the polls remains to be seen.

“This is a battle for voter turnout and a battle for independent voters, which we’ve said all along,” Madonna said.

The spotlight’s shining even brighter on the race following the candidates’ first televised debate Wednesday night in Philadelphia, with another showdown scheduled in Pittsburgh tonight. While neither candidate can claim any major victories following Wednesday night’s event, Madonna said Sestak, who has struggled in debates in the past, gave his best debate performance to date and surpassed the lowered expectations he faced. During the debate, Sestak attempted to link Toomey to extreme national figures in the political party like Christine O’Donnell, the Republican Senate candidate in Delaware and Sarah Palin. Madonna said that strategy may be having the desired effect for Sestak.

“There are some people who say the O’Donnell commercials in the Philly TV market are influencing our elections here in the suburbs,” Madonna said. “And that her commercials may actually make the more independent-minded voters nervous.”

Another sign that voters in Philadelphia and its surrounding suburbs are more likely to show up at the polls: Democratic Governor Ed Rendell’s approval ratings were up slightly in this week’s numbers, an indication that more party-line Democrats who view the governor favorably are being included among likely voters.

Others explain Sestak’s late surge by citing his reputation as a “comeback kid” after his eleventh-hour victory over Arlen Specter in the primaries. Madonna acknowledged Sestak’s impressive come-from-behind win in May, but said that won’t necessarily be the case on Nov. 2.

“What happens is you get a narrative going here and it becomes sort of self-fulfilling. General elections are different than primaries,” Madonna said.

He added that in the primary, low voter turnout benefited Sestak. In the general election, Democrats in general face the opposite problem, and there’s no reason to expect Toomey to slow down or lose any steam in these final days before voting day.

The gubernatorial race is making fewer waves in polling numbers, but one poll released Wednesday by Public Polling Policy shows a much smaller lead for Republican Candidate Tom Corbett. According to PPP, he leads Democratic candidate Dan Onorato by only two points, 48 percent to 46 percent. The same Morning Call/Muhlenberg College poll that showed big gains for Joe Sestak found Onorato trailing by nine percent, close to where he’s been for the past few months.

Madonna said Onorato is bound to see a bit of a boost due to the apparent Democratic bump in enthusiasm, but said he still has a lot of ground to cover before he catches Corbett.

“The democratic base is becoming more motivated, and for those voters it’s a straight party vote,” Madonna said. “I think that’s what’s going on more so than some surge by Onorato based on his commercials or the debates. But to come back from 10 to win — that was the polling average — that would be truly be a feat,” he added.

Polling numbers in the states many contested Congressional races have been conspicuously lacking, but numbers from The Hill 2010 Midterm Election Poll continue to show close contests. Outside of Philadelphia Democratic incumbent Patrick Murphy is clinging to a small lead over Republican Mike Fitzpatrick, 46 percent to 43 percent. In the Northeast, Chris Carney is tied with Republican challenger Thomas Marino at 41 percent.