On the entire 11th floor of an office building at the top of Michigan Avenue's Magnificent Mile, more than 100 mostly young political activists sit at laptop computers, training and plotting for a new American revolution.

For this very early stage of a presidential campaign, they constitute an unprecedentedly large army of paid recruits in the grassroots effort to make Sen. Barack Obama of Illinois in 2009 the first U.S. president of mixed racial parentage.

According to campaign manager David Plouffe, over the last weekend the headquarters here oversaw a canvass of 10,000 volunteers knocking on doors and ringing doorbells across the country, collecting names and contributions to keep the Obama phenomenon rolling.

On a daily basis as well, he says, canvassers are doing the same in the first four states to hold presidential caucuses or primaries in 2008 — Iowa, New Hampshire, South Carolina and Nevada, where staffs are already in place.

"I think we've had an extraordinary journey here," says David Axelrod, the veteran Chicago strategist who engineered Obama's election to the U.S. Senate in 2004 and is trying to do the same for his presidential bid. That journey, he says, has come "as close to a draft as I've seen in my lifetime, in American politics."

The headquarters layout here more than rivals the operation of four years ago in rural Burlington, Vt., in which a similar collection of mostly young and Internet-savvy people propelled former Vermont Gov. Howard Dean as frontrunner in the 2004 race for the Democratic presidential nomination.

That earlier assemblage tapped into anti-war sentiment that funded and fueled a Dean campaign that rose like a rocket in 2003 but crashed in the Iowa caucuses in 2004. The Dean headquarters had in ways the look of a Vietnam-era commune with a fire-breathing candidate who turned out to be too hot for voters to handle.

The Obama headquarters appears to burn under a lower flame, though the candidate himself employs much the same anti-war rhetoric with which Dean castigated President Bush's invasion of Iraq and its aftermath. Based on the Democratic debates so far this year, Obama comes across as more controlled and less angry than Dean was in his expressed opposition.

The circumstances of the competition for the 2008 Democratic presidential nomination may account for some of the difference. In 2004, Dean stood out in his unambiguous and uncomplicated criticism of Bush and the invasion against such party rivals as Sens. John Kerry and John Edwards, who had voted to authorize use of force in Iraq.

This time around, a consensus has formed among the Democratic presidential hopefuls that the war must be brought to an end, with the internal debate on how and how soon this goal can be achieved. Obama, who was only running for the Senate at the time that first critical 2002 vote was taken, nevertheless was on public record against the invasion, warning of the disastrous outcome it could yield.

The Obama phenomenon has obviously been motivated by wide public opposition to the war, Axelrod says. "But there's also a general sense that our politics have failed us, that Washington is in disarray at a time we have huge problems that have to be dealt with, and that the hyper-partisanship, the hyper-ideology, the hegemony of special interests, has made it impossible get anything done. The people are hungry for someone who can cobble the American community back together, and focus the country on the national interest."

For all the front-loading of the 2008 primary calendar, Iowa's caucuses as the kickoff event remain critical for the momentum that success can bring the winner. Edwards has led the polls there, but Obama is being introduced to Iowa voters in a mailing of 12-page flyer and a DVD to 100,000 voters.

A measure of the grassroots reaction to Obama's candidacy is the $26 million raised in the first reporting period of 2007, keeping him competitive with Sen. Hillary Clinton and ahead of Edwards among the trio of Democratic frontrunners in the national polls. So the second-quarter report due June 30 will be watched with particular interest.

Jules Witcover's latest book, on the Nixon-Agnew relationship, "Very Strange Bedfellows," has just been published by Public Affairs Press. You can respond to this column at juleswitcover@earthlink.net.