WASHINGTON — When Tea Party activists swamped town hall-style meetings about health care in the summer of 2009, President Obama's army of campaign volunteers largely stayed away, seemingly less interested in fighting for legislation than they had been in electing the nation's first African-American president.
Now, Mr. Obama is seizing a second chance to keep his election-year supporters animated.
With lawmakers scheduled to return to work on Monday to begin intense discussions before a looming fiscal deadline, Mr. Obama's aides are trying to harness the passions that returned him to the White House, hoping to pressure Republicans in Congress to accept tax increases on the wealthy. The president's strategists are turning first to the millions of e-mail addresses assembled by the campaign and the White House.
Already, supporters are being asked to record YouTube videos of themselves talking about the importance of raising taxes on the rich. Aides said those videos would be shared on Facebook and Twitter and would be forwarded to centrist Democrats, as well as to mainstream Republicans, who they hope will break with their Tea Party colleagues.
An e-mail last week urged activists to share with their friends a graphic explaining the president's tax argument. And Mr. Obama's campaign manager sent an e-mail appeal asking supporters to fill out a survey about issues they would like to stay involved in.
The president is planning rallies in influential states to remind supporters of the need to keep the pressure on lawmakers during the fiscal talks. And should negotiations break down, Mr. Obama's team is arranging for Republican lawmakers to hear from of tens of thousands of riled-up activists through angry Twitter posts, e-mails and Facebook messages.
"If Republicans refuse to move, if they refuse to cooperate, then you've got to be willing to engage the American public," said Representative Chris Van Hollen, a Maryland Democrat and important Obama ally. The campaign machinery, he said, "will respond to the president calling upon it to get engaged."
As Mr. Obama tries to motivate his army of supporters, his rivals will be working to do the same. Republicans have acknowledged that they did not match Mr. Obama's campaign operation, but in the tax fight, the party and its allies will also be using technology.
The Republican National Committee has turned to Twitter regularly to talk about the impact of tax increases on small businesses, using the hashtag #StopTheTaxHike. And the U.S. Chamber of Commerce has begun a multimedia campaign that it says is intended to prevent a financial disaster if Congress and the president do not reach an agreement.
The chamber's site has a "Fiscal Cliff Countdown" clock, a calculator to determine "your post-taxmageddon taxes" and links to e-mail members of Congress.
Republicans in Congress will not have access to the kind of national list that Mr. Obama does. And yet it is not certain that Mr. Obama and his allies will be any more successful in motivating his followers than they were during the postelection period four years ago.
The fiscal negotiations are taking place behind closed doors, and to reach a deal with Speaker John A. Boehner, Mr. Obama will probably have to make compromises that could undermine the fervor of his most ardent supporters.
"The big issue they are going to have to figure out with the list is that activists want to fight for issues they can believe in," said Eddie Vale, a spokesman for Protect Your Care, a liberal advocacy group. "A call to cut a bipartisan deal — that's not going to cut it."
At the same time, the White House needs to avoid overplaying its hand and antagonizing Republicans to the point where a deal becomes impossible.
Obama aides view keeping their grass-roots supporters energized as important to the president's second-term success on broader tax changes, an immigration overhaul and efforts on climate change.
In his first term, Mr. Obama's yearlong battle over health care failed to inspire the millions of activists from his 2008 campaign to put pressure on Republican lawmakers. "We were stunned that it never showed up," said a senior member of a pro-health-overhaul interest group, who asked for anonymity to avoid angering the White House. "They had this thing built, and we were waiting for them to turn it on, and it just never came."
Later on, Mr. Obama's team did more to rally pressure on his adversaries. The president succeeded in fights with Republicans to extend the payroll tax cut in 2011 and to change student loans.
"There's always a challenge between rallying cry issues and the challenge of governing," said Neera Tanden, the president of the Center for American Progress, a liberal research group. "It's one that I'm confident he can navigate."
The first test of the mobilization efforts will come quickly, as the president pushes the tax issue during the lame-duck session of Congress. The idea, aides say, is to marry old-fashioned phone calls to the offices of wavering lawmakers with the latest social media tools.
Unions and progressive groups have made a Web site, theaction.org, calling for an end to "the Bush tax cuts for the richest two percent." Supporters are encouraged to download an "action kit" that includes materials needed to make signs, letterheads and Web site banner ads — all arguing for an end to the tax cuts.
One sign that can be printed out says "Middle Class Over Millionaires." Another says "Fairness & Progress from Congress." A typical banner advertisement that supporters can download and post on their Web site says "End the Bush Tax Cuts for the Wealthy."
Visitors to the site are also given the option of expressing their support for Mr. Obama with a single click that creates a Twitter message: "The election is over. Don't rest. Join the action. The action to end the Bush tax cuts for the rich. #theaction."
Another button on the site takes visitors to a Facebook page that can be used to organize meet-ups for the tax fight.