(CBS News) WASHINGTON - Unions are campaigning hard to re-elect President Obama. That means raising and spending plenty of campaign cash. But it also means getting out their ground game.
During his 2008 campaign, Barack Obama raised $745 million -- shattering records and outspending rival John McCain nearly 2 to 1.
In 2012, however, he's being outspent -- not by Mitt Romney, but by outside groups, including super PACs.
Conservative super PACs have already spent more than $97 million this year, funded heavily by wealthy individual donors. Liberal groups have spent just under $13 million.
But of the top ten organizations that give to super PACs, only three are conservative, and seven out of the top 10 are labor unions.
"Unions have always been more partisan, and so they will be as aggressive this year as they possibly can again this cycle in support of Democrats," said Bob Biersack of the Center for Responsive Politics. He also said unions are expected to spend at least $300 million this campaign.
But their real power isn't just the money, it's also their ability to organize.
Karen White is the national political director for the National Education Association, the largest union in the U.S. "There are three million of us who are members of the National Education Association. We really are going to be boots on the ground," she said.
The NEA has already given more than $4 million to Democratic super PACs. White said labor groups don't need to outspend Republicans.
"It's never going to be a money game for us," she said. "It's always going to be about how many of our members we can get out there and educate the public.
Tuesday's recall election of Wisconsin's Republican Governor Scott Walker will be a good test of not only the Democrats' ability to raise money, but the effectiveness of their ground game.