Matt Eison's passions had included soccer, guitar and traveling, but never politics.

Yet there he was Monday night outside a popular Center City gay bar, Woody's, clipboard in hand, trolling for voters to register to support Barack Obama.

"If there's ever going to be a black president of the United States, this is it," said Eison, a 35-year-old married pediatrician. "He's a uniter. He's the best political speaker in a generation. He's our Bobby Kennedy."

Eison exemplifies the highly visible grassroots energy generated by the Obama campaign, which has helped lead to record primary turnouts in other states. With Pennsylvanians preparing to cast their primary ballots April 22, the campaign is hoping to replicate the historic trend here.

As the Illinois senator trails Hillary Rodham Clinton in the polls in Pennsylvania, priority No. 1 for his campaign is registering as many voters as possible - at least 100,000 - before the March 24 deadline. (In the closed primary, only registered Democrats - there are 3.89 million statewide - can cast ballots for Clinton or Obama.)

While Obama's goal is to expand the Democratic electorate in Pennsylvania, Clinton is hardly as focused on doing the same. The New York senator's campaign said it had no similar voter-registration drive because that is not central to its strategy; Clinton has done better in closed-primary states, so it is not a necessity for her to lure independents, Republicans or new voters.

The Obama campaign is largely going after the coalition of voters it has relied on to win elsewhere: African Americans, college-age students, and independents who register as Democrats for the primary.

And that puts a spotlight on Philadelphia and Pittsburgh, and nearly every college campus in between.

"We come to this state as the underdog," Obama spokesman Sean Smith said. "What we can do is roll up our sleeves and get to work and try to overcome some of the institutional advantages the Clinton campaign has here in Pennsylvania. . . . We're out registering as many people as we can."

A key target are the state's 35 largest colleges, where, the campaign estimates, 327,000 undergraduates are up for grabs. Dozens of organizers have been dispatched to secure those voters.

Temple Students for Barack Obama, for instance, is a campaign-sanctioned group with "dorm leaders" and "dorm captains" responsible for visiting every residence hall to find new voters.

At St. Joseph's University yesterday, two Boston University students spent the afternoon calling out, "Are you registered to vote?" Stephanie Gottsch, 19, of Mount Ephraim, said she and friend Amy Baral, 18, of Connecticut, "saw openings for student interns with the Obama campaign" and decided to come.

The Obama campaign is also focusing on geographical areas where they see the potential for big returns.

Gregory Walker is a "team leader" with the Obama for Center City volunteer group. His focus includes the candidate's appeal to gay and lesbian voters, which led him to Woody's on Monday night. But, he said, "I'm interested in registering any voter."

While the campaign is organizing voter registration, it also is benefiting from unaffiliated grassroots efforts.

Third-year Temple University law student Molly Armour is part of Temple for Obama, a group of "Barack supporters who just found each other," as she put it.

For weeks, her group has staffed a table in the Student Activity Center. When classes resume after spring break this week, Armour said, "I will be standing up at every one of my classes and saying, 'It's time to register, or it's time to switch.' "

Obama's appeal to the young also is evident at vote-rich African American churches.

"This election has caused a lot of attention. I'm excited about the number of teenagers I'm experiencing who want to know more about it," said the Rev. Alyn E. Waller, senior pastor of the 12,000-member Enon Tabernacle Baptist Church in Philadelphia, which is prohibited from endorsing a candidate but is registering voters.

Sneaker Villa, an urban clothing retailer, has boxes with voter-registration forms at each of its 16 Pennsylvania stores, including eight in Philadelphia. Its executives, who support Obama, consider raising political awareness part of the retailer's mission to improve the communities where its stores are.

"We want to get young people in so they will have a voice," 22-year-old salesclerk Chuck Lee said. Outside Sneaker Villa's West Philadelphia store at 52d and Market Streets, Lee spent part of Monday blasting his message through a microphone: "You're not too young to start voting! Come on, walk up and do it!"

The campaign embraces all the help it can get.

"A certain amount of initiative you have to just let occur," said consultant Tom Lindenfeld, who designs get-out-the-vote efforts for Obama. "If you get too bureaucratic about it, you might stymie some of the energy."

Manayunk's 21st Ward leader, Lou Agre, represents some of that unregulated energy. Agre, an Obama supporter, is planning a door-to-door hunt for new voters in next week. "There's a lot of young college graduates who live there, and demographically they are more likely to be Obama supporters than Hillary," he said.

After meeting Monday with Obama campaign officials, State Sen. Anthony Williams (D., Phila.), a 20-year elected official, said he had formed a mini-operation of sorts, encouraging former campaign aides, particularly younger staff, to "return to their college campus and start their own quasi-organization to do registration."

For all the effort, the effect of the voter push - which will likely intensify in the next two weeks - wasn't clear yesterday.

State election officials did not have up-to-date registration figures to release yet.

In Philadelphia, Board of Elections figures showed that the number of registered Democrats grew by 6,079 between Feb. 11 and Monday. Conversely, the number of Republicans dropped by 669. In all, there were 759,449 registered Democrats.

"These numbers don't show any great wave," elections administrator Bob Lee said. They also give no indication of whether any bounce, now or later, will benefit Obama or Clinton.

Nonetheless, new registrations are key to any potential Obama victory in Pennsylvania, said political analyst G. Terry Madonna of Franklin and Marshall College in Lancaster.

"It's obvious that the way he is winning the caucuses is that his voters are highly motivated, they turn out, they are well-organized. That's been the price of gold for him," Madonna said.

"He is continuing to do here what he has done in other states. The question is: Is it enough?"