ERIE, Pa. -- Sen. Barack Obama borrowed a gymnasium at a local college here, pumped in high-volume music and higher volume supporters as the Pennsylvania Primary rushed into a final weekend in which political rallies seem to speak to the converted amid rock concert atmospherics.

Easily 3,000 people stood in line hoping for an estimated 1,800 spots open at the Junker Center at Penn State's Behrend Campus, a train of hopefuls that stretched down a rolling hillside an hour before doors opened and nearly three before the event was set to begin.

An hour-long survey of those in line turned up only one who hadn't already decided to vote for the Illinois senator in Tuesday's Democratic presidential primary. For most, it was the chance for a jolt of excitement in a presidential election that will make history by putting either a woman or an African-American on the national ballot and, conceivably, in the White House.

"It's more like a concert. He's like a celebrity," said Keith Szalabawka, a 22-year-old shop worker from nearby Harborcreek.

"That's pretty much what it is," piped in Mr. Szalabawka's companion, David Guilford. "Just to see the man. It's a good time. He's sweepin' the nation."

Whether Mr. Obama can sweep Pennsylvania is still very much in doubt. Polls have consistently put him behind his main rival, New York Sen. Hillary Rodham Clinton, although his campaign hopes a combination of momentum and charisma can narrow the race enough to make a Clinton victory here Pyrrhic.

Multiple polls have generally shown a Clinton lead of from 5 to 9 percentage points over Mr. Obama, with two others placing the race as a statistical tie.

Undecided voters, once reliably double digit, have fallen to a handful that could hold the balance in deciding whether the marathon for the Democratic nomination is to end before summer.

With the contest closing, Mr. Obama today turned to swelling oratory, aiming for a final glow by sketching a tableau of a nation mired in an unnecessary war in Iraq, weighted down by rising energy prices and dragged into an economic mire amid record home foreclosures.

"We can't wait to fix our schools, we can't wait to fix our health care system, we can't wait to bring good jobs here to Erie, Pennsylvania -- we can't wait," Mr. Obama told the crowd.

He was drowned out by chants of "We can't wait! We can't wait!" His sole swipe at Mrs. Clinton was a criticism of the business-as-usual attitude that he said was exemplified by her remarks that lobbyists have a role in the public debate over issues.

He promised that the sometimes bitter rivalry for the nomination would not harm the party's chances at the ballot box in the autumn.

"I know that a lot of people have been worried about how long this Democratic contest has been going," he said. "Let me tell you something: Our party will come together. Our party will come together in August.

"Not only will our party come together, but we're going to try to get the independent voters and disaffected Republicans."

So convinced was today's audience, which began cheering the candidate even as it waited in line to hear what he might say, that it raised a question: why would people who have already decided how to vote stand in line for hours, possibly without hope of getting into an event ostensibly intended to persuade people who watch it on the evening news?

Pam Davis, an Erie woman who changed her registration from Republican to Democratic and then brought her 16-year-old daughter, Sarah, with two teenage friends in tow, said it was a matter of being present at history.

"I have three teenagers here that have an opportunity to be inspired by a young candidate that we're hoping some day will be president. I want to be a part of it," Mrs. Davis said.

A man standing next to her put it more bluntly, before rushing off: "It's the same reason I wait in line to watch batting practice before the game."

Precisely what some have been seeing while watching the candidate sometimes less resembles a batting practice than a Rorschach blot.

Yesterday, two men waiting in line, each expounded on Mr. Obama's position on Iraq.

"He has a really good plan for coming out of Iraq," said Brandon Frazier, 19, of Warren County. "His plan is to pull out slowly instead of just coming out all at one time. So we retain what we've gained over there."

Mrs. Clinton, said Mr. Frazier, "just wants to pull out real quick. It would go back to the way it was."

Dave Frank, a middle school teacher from nearby Franklin Park, laid out Mr. Obama's Iraq strategy this way: "His position is to get out of Iraq as quickly as possible. It's not one that I totally agree with because … we can't out and out leave immediately. It's got to be a phased withdrawal."

Both men are foursquare for Mr. Obama -- whatever his stand.

That left Alicia Tavani, 20, a student from nearby Gannon University. She had come not to worship at the shrine but to hear the traveling prophet Obama and decide if his words would earn her vote or if she would join her mother in the Church of Hillary.

"There's really no one big issue," Ms. Tavani said.

"A lot of their stands are kind of similar. I'm torn.

I think they're both great candidates that could be awesome presidents."

Ms. Tavani attended a Clinton speech earlier in the primary season.

"She hit all of the major topics and I really feel like she had the whole crowd involved," she said.

What was Ms. Tavani looking for today? "I'm looking for the same thing. I'm looking for that great presence that I've heard he's had. And I'm looking for him to hit all the facts and address all the issues so we know head-on what we're getting into."

With that, the line edged into the hall where the warm-up music, played at stratospheric volume, included Bruce Springsteen's "Born to Run." It would remain for Mr. Obama to persuade the handful of Alicia Tavanis remaining in Pennsylvania, that he was born to run the country.