I headed downtown to enjoy some peaceful reflection on the Mall, placing the night’s events in the context of Abraham Lincoln’s immortal words enshrined in his memorial.

My plans were quickly scrapped, however, as I approached the White House. Throngs of ecstatic D.C. residents of all shades and ages honked their horns, chanted “O-BA-MA” and “Yes we did!” and hugged passing strangers.

Never had I seen such unadulterated joy in the streets of the United States. The scene most closely resembled a World Cup victory celebration.

In front of the White House, a swarm of revelers sang George W. Bush out of the presidency: “Na, na, na, na, hey hey, goodbye.” Even a Republican, had one been present, would have taken comfort in this raucous reminder of the persistent freedoms that are at the core of American democracy.

The tens of thousands of people cheering here in Grant Park, at what is shaping up to be one of the largest victory celebrations in U.S. political history, are not just heralding another barrier broken in America. They are honoring a promise fulfilled — the advancement of a rare political leader who addresses the public honestly, engages his opponents respectfully and communes with his supporters openly. He built an agenda through a participatory politics that empowers organizers and upends civic culture by expanding the electorate.

In political terms, that means that Obama did not win “red states” Tuesday by treating them like red states.  He did not energize his base by neglecting it.  He did not convert wing voters by pandering to their occupational and cultural identities.  After all the soundbites piled up, in fact, it was still Obama who had an actual policy conversation with Joe the Plumber, while Sen. John McCain invoked the everyman as a human prop.

Across the country,  people,  with their votes and their activism, are embracing the “change” agenda. Some scuffling over credit, priorities and ideology is inevitable, but the basics are clear: end the Iraq war; renew the economy; conquer corruption; prioritize alternative energy; pursue universal health care; and renew our civic life with a politics of good faith.  It is ambitious, difficult and long overdue.

Security appears more onerous than usual.  One person told me they knew people who got in line at 4 p.m. and were still waiting four hours later to get in. Some gates did not open to the public until 6 p.m.  But those who made it inside are boisterous, from what I could tell from a recent walk around the grounds. People cheered wildly at the news that Pennsylvania’s 21 electoral votes were in the Obama column, according to CNN and MSNBC.

For what it’s worth — very little — the press here is convinced Obama will win by a lot tonight.

There’s a small strip of coveted real estate between the stage and the largest bank of TV cameras I’ve seen on the campaign trail this year. The rest of the crowd will fill out a huge aisle of the park, facing the stage at something like an 80-degree angle. Most will watch tonight’s speech on JumboTrons dotted throughout the park. (There are almost no attendees here yet.)

In the press filing center, CNN is playing on two big screens, and about 100 reporters are milling about the half-empty tent. People are buzzing over some early, unreliable exit polls that suggest Obama leading in virtually every key state. As Laura just posted, exit polls are hardly a basis to buzz in any direction.

Meanwhile, Obama has been (finally) relaxing — he played basketball with friends and returned to a nearby hotel at about 5:10pm.

Letting us know what it’s like in the press center, here’s her first Election Day video:

Instead of appearing before a throng of supporters at the Biltmore Hotel in Phoenix on the evening of Nov. 4, the Republican presidential nominee plans to deliver post-election remarks to a small group of reporters and guests on the hotel’s lawn.

Aides said Thursday that the arrangement was due to space limitations, and that McCain might drop by the election watch party at some other point.

McCain’s remarks will be piped electronically into the party and media filing center, aides said. Only a small press “pool” — mostly those who have traveled regularly with the candidate on his campaign plane, plus a few local Arizona reporters and others — will be physically present when he speaks.

The news calls into question whether the $695 price tag for a workspace in the media filing center at the Biltmore will be worthwhile for news organizations.

Yet it seems a fitting finale for a campaign in which many reporters following McCain saw more of him on television than they did in person.

In contrast, Sen. Barack Obama is planning a massive event in Chicago’s Grant Park — the site of the Lollapalooza music festival. He is expected to put in an appearance at his party.

UPDATE: Marc Ambinder reports the McCain campaign disputes the AP story:

A McCain aide says:

“He’ll speak outdoors on the lawn in front of backlit Camelback mountains — it will be beautiful — and 2000 plus people will be out there with him. The rest of the guests will be in ballrooms and overflow tents with widescreen TV’s.”