ORLANDO, Fla. — The AFL-CIO formally endorsed President Obama's re-election bid Tuesday, with the nation's biggest labor organization vowing to mount a vast door-to-door effort for Democratic candidates in response to the flood of outside political money that conservative groups are pouring into the campaign.
The labor federation said its strategy is to devote less money than it did in 2008 to specific candidates' campaigns and Democratic campaign organizations and put more emphasis on old-fashioned, get-out-the-vote shoe-leather.
Although the endorsement was widely expected, it does provide a major boost in manpower and ground troops for the president's re-election campaign. AFL-CIO political director Mike Podhorzer said up to 400,000 union members will be staffing phone banks and knocking on doors to persuade voters to support federal, state and local candidates.
"We're not going to ever raise anything like the kind of money that our opponents have," Mr. Podhorzer said. "But the power of people talking to each other, friends talking to friends, friends talking to neighbors, is always going to trump these cheap, negative ads."
The strategy, announced at the AFL-CIO's annual winter executive council meeting near Disney World, marks a shift from two years ago, when about two-thirds of organized labor's political spending went directly to candidates and party campaign committees, Mr. Podhorzer said.
Unions hope to take advantage of a 2010 Supreme Court decision that allows union campaign workers to stop at the homes of any voter, not just those of union members, the labor organizer said. The same ruling allows corporations and unions to spend unlimited cash in support of, or against, candidates for elected office.
Union leaders have said they plan to spend more this election cycle than the $400 million they say they spent helping elect Mr. Obama and other Democrats in 2008.
AFL-CIO President Richard Trumka said all 57 affiliates of the labor umbrella group voted to back Mr. Obama.
"President Obama honors the values of hard work, of mutual respect, and of solving problems together - not every person for himself or herself," Mr. Trumka said in a statement. "Each of the Republican presidential candidates, on the other hand, has pledged to uphold the special privileges of Wall Street and the 1 percent."
Mr. Trumka told reporters unions are more enthusiastic about the Democratic president than they were a year ago, when Mr. Obama was mired in a debate with House Republicans over deficit reduction and didn't seem focused on job creation.
"I think he's made a complete pivot," Mr. Trumka said of Mr. Obama.
Mr. Obama addressed the executive council Tuesday via conference call and thanked them for their support. His campaign manager, Jim Messina, addressed union leaders in person.
Mr. Podhorzer wouldn't say exactly how much the AFL-CIO itself will spend this cycle. The federation, which represents 57 unions and about 12 million members, spent more than $53 million during the 2010 campaign cycle.
The federation is devoting most of its attention to six battleground states: Florida, Michigan, Nevada, Ohio, Pennsylvania and Wisconsin. It also hopes to register at least 20 percent of an estimated 2.3 million active and retired union members who are not registered to vote.
A spokeswoman for GOP front-runner Mitt Romney dismissed the union endorsement as payback for favors she said the Obama administration had done for the labor movement, a key part of the Democratic Party base.
"Big labor unions spent hundreds of millions of dollars to elect President Obama, and he has been repaying them ever since," said Andrea Saul, a spokeswoman for Mr. Romney. "Union bosses have repeatedly attacked Mitt Romney in this campaign because they know he will end the sweetheart deals they have enjoyed under President Obama."
Mr. Trumka hit back at the former Massachusetts governor in his own talk with reporters Tuesday.
"Mitt Romney doesn't have a clue what workers go through," Mr. Trumka said.