Senator Barack Obama implored thousands of admirers who gathered last night in New York City to set aside their distrust in politics and believe in the long-term possibility of his presidential candidacy even though, he conceded, “there are easier choices to make in this election.”
In a giant rally in the backyard of Senator Hillary Rodham, Mr. Obama, of Illinois, drew distinctions between himself and his leading rivals for the Democratic presidential nomination, insisting that only a fresh candidate could truly change Washington. Twice, he singled out Mrs. Clinton.
“Even your senator from New York wasn’t clear about the Yankees,” he said, laughing at his own joke. “I know who I’m rooting for!”
Mr. Obama was referring to a moment in the debate Wednesday when Mrs. Clinton, who grew up in Illinois, said she would alternate sides between the New York Yankees and the Chicago Cubs should they ever face each other in a World Series. He broadened his criticism, suggesting voters should be dubious of any candidate who declined to acknowledge the prospect of raising taxes to fix Social Security.
Mr. Obama, bathed in bright flood lights as he stood on a stage before a crowd stretching across Washington Square Park, struck a sharper tone than he has through much of his campaign, particularly when he stands alongside his Democratic rivals. The arguments he made, before an audience of supporters, were not articulated during a debate one night earlier.
“There were folks on the stage that said Social Security is just fine, we don’t have to do anything about it,” Mr. Obama said last night. “There are those who will tell you that getting out of Iraq will be painless, we’ll do it in a snap, not acknowledging that there are no good options in Iraq. There are folks who will shift positions and policies on all kinds of things depending on which way the wind is blowing. That’s not the kind of politics that will deliver on the change we are looking for.”
The racially diverse crowd included Obama devotees who said they came specifically to increase attendance; Greenwich Village residents who had heard the commotion and followed it with dogs and yoga mats in tow; and nostalgists who beamed at the sight of thousands of mostly young people filling the park for a liberal, antiwar cause.
Though Mr. Obama and the other candidates have spent most of their time in the early voting states of Iowa and New Hampshire, the rally last night underscored efforts to look ahead to Feb. 5, when New York and 20 other states hold primaries. Mr. Obama has made at least 17 trips to New York City this year.
While Mrs. Clinton is expected to carry the state, Democrats split their delegates proportionally, so Mr. Obama believes he could win enough delegates to make a difference in a tight race.
“The challenge that we have today is restoring a sense that politics is not just a business, but that politics is a mission,” Mr. Obama said, “that power doesn’t have to always trump principle, that we can expect from our leaders that they are going to tell the truth and be honest about the problems that we face and they’re not going to equivocate and hedge and hem and haw.”
Initially, the crowds extended to the far borders of the park, massed behind metal detectors that were brought out for the first time in the 2008 campaign. Unable to hear the introductions, people started to leave. But after chants of “Let us in!” security gave up and the crowd filed in.
Mr. Obama’s aides said more than 20,000 people registered for the event through the campaign’s Web site. While it was impossible to determine even a reliable attendance estimate, view from the vantage point of an elevated lift seemed to reveal the gathering as one of the largest campaign events of the year.
Sophie Ragir, 18, a Columbia freshman, said, “It’s a social thing. Everyone on my floor was, like, are you going to the Obama thing?”
Leyla Biltsted, 60, who is retired and lives in Manhattan, said, “I’ve never heard such a wonderful visionary speech as he did at the Democratic convention. That brought me hope.” She added: “Now, I’m waiting to see what’s behind the vision, how he’s going to implement it, who he’s going to surround himself with. We don’t vote for a little while yet; I’m on a fishing trip.”