WASHINGTON, D.C. March 17, 2011  -- President Obama met in a closed hotel ballroom Wednesday evening with the core of his 2012 fundraising team, a group of nearly 500 supporters that by some estimates will be called on to help Obama raise upwards of $1 billion towards his reelection.

The gathering, arranged by the Democratic National Committee, was the latest move in the quiet start-up of the president's 2012 fundraising apparatus. The effort has been slowly getting underway in small, closed-door meetings between Obama's political advisors and his top fundraisers for the past several weeks.

"I think the president knows what's ahead of him," said Mitchell Berger, a veteran Florida fundraiser and advisor to Democratic campaigns dating back to the Carter years, who attended Wednesday event. "When I got started in 1976, we were trying to raise $100 million. You can imagine what that is adjusted for inflation."

As the incumbent president, and someone with a proven record of raising $750 million in his last election, experts agree Obama is well-positioned for what's ahead. But they also tell ABC News there will be new obstacles to his fundraising effort that precipitated this early start.

Some of the faces in the crowd that lined up to pass through security screening in the lobby of the Marriott Wardman Park hotel Wednesday were mainstays of Obama's 2008 bid -- corporate executives, union leaders, and top lawyers capable of tapping their vast networks of friends to raise, in some cases, close to $1 million each. They included past supporters such as Ned Lamont, the former Senate candidate from Connecticut, Florida businessman Mark Gilbert, and venture capitalist Steve Westly.

In 2007 and 2008, Obama assembled an army of so-called "bundlers" -- named for their ability to bundle large numbers of checks in relatively small increments, keeping each individual donor under the legal giving limit, which now stands at $2,500. But political experts agree that the president will confront significant new challenges as he begins to restart that machinery.

Obama Fundraisers Become Ambassadors

For starters, Obama put some of his most proven fundraisers out of commission by turning them into top advisors and overseas ambassadors, making it illegal for them to engage in campaign activity. Among them are a big slice of his top-tier bundlers -- those who raised more than $500,000. They include more than 50 ambassadors, from California bundler Jeff Bleich in Australia to Boston fundraiser Alan Solomont in Spain to Chicago moneyman Louis B. Susman in the United Kingdom -- prized hand-outs to those who brought in large sums at critical points in his campaign.

He will also lose the fundraising clout of senior administration officials such as Julius Genachowski, who now chairs the Federal Communications Commission, and Bill Kennard, whom Obama appointed as U.S. ambassador to the European Union.

A key strategy for replacing those lost to administration posts has been the active recruitment of Democrats who backed Hillary Clinton last cycle. "They're going after the Clinton people," one veteran Obama fundraiser told ABC News. The targets are bundlers such as Florida's Ben Pollara, who says on his website he raised over $12 million for Clinton as her Florida finance director.

At the same time, Obama will have new challenges reaching out to the unprecedented base of small-dollar donors he was able to reach through the internet. In addition to trying to raise money during a much tougher economic climate, Obama will also have to generate excitement among supporters who sent him money because he was the face of change.

"Certainly he faces the loss of his bundlers, many of whom are now in the administration somewhere," said Meredith McGehee, policy director of the Campaign Legal Center. "But he also faces a base that is probably not as gung ho because he's actually had to govern. When you govern, you don't throw as much red meat to that base."

One advantage in that effort will be the massive list of email addresses and cell phone numbers that the campaign gathered during hundreds of rallies and house parties during the course of the 2008 campaign. Another will be support from within the high-tech community, including Google CEO Eric Schmidt, who has pledged to advise the campaign, according to a top Obama supporter.

Democrats Expect 2011 Attacks in Battleground States

McGehee also noted that the President will have to raise money in a new legal environment, where outside groups now have the ability to operate free of past strictures -- often without ever revealing where their money originated. Democratic officials told ABC News they expect to spend 2011 fending off attacks in key battleground states from groups such as the Karl Rove-backed American Crossroads.

If Wednesday's crowd was any sign, though, there will still be no shortage of people to line up for the job of corralling hundreds of thousands of dollars for the president's re-election bid.

During the event, Obama did not discuss his fundraising challenges, but instead used it as an opportunity to rally his troops, according to several who attended.

The more pointed message came later, in smaller dinners around Washington that included access to other top Democrats, and follow-up talks from Kaine. Guests were advised that admission to the National Finance Committee involved raising $350,000 for the party and a separate White House victory fund by the end of 2011.

Still, those ready to sign up stood in long lines that snaked through the cavernous lobby of the Washington, D.C., hotel.

DNC officials staffing the event estimated that 480 people attended. They classified many of those in the room as "potential supporters" -- new recruits for a massive undertaking that is all too familiar to those seeking the White House.

Click Here for the Blotter Homepage.