U.S. President Barack Obama's re-election campaign launched its first TV ads on Tuesday in an effort to boost enthusiasm among his base."The 2012 campaign is under way and the outcome will depend not on what I do, but what you do," Obama said in one of the two 30- second ads. "It all starts with you making a decision to get involved because we've got so much more to do."The enthusiasm of the president's core base -- African-American and Latino voters, women, college students and young voters -- is considered critical for his re-election campaign because it could establish better networks across the country and promote a higher turnout rate on Election Day.A number of surveys showed that Democratic voters are far less enthusiastic about the current presidential race than they were in 2008 -- a bad sign for Obama who is already facing strong headwind from dissatisfied Americans about the current situation in the country.Forty-five percent of Democrats and Democratic-leading independents said they are more enthusiastic about voting than usual, in sharp contrast to 2008 when the number reached as high as nearly 80 percent, according to a Gallup poll conducted in September.The survey also showed an enthusiasm gap between Democrats and Republicans, with nearly 6 in 10 Republican voters describing themselves as more enthusiastic about voting.Obama's re-election campaign has so far employed a variety of tactics to reach out to voters, including neighborhood gatherings, one-on-one meetings, and voter registration drives. This led some Republicans to attack the president, accusing him of caring more about winning a second term than resolving the nation's problems.White House Press Secretary Jay Carney rejected claims on Tuesday that Obama spends too much time fundraising and doing political work, stating instead that the president only focused on the re-election campaign about "5 percent of his time."