Which do you think is more effective in a political campaign? Having lots of campaign workers and volunteers organized in key districts, knocking on doors, working the phones, handing out flyers, and getting out the vote? Or running lots and lots of television ads?
We’re going to see which strategy works better. The Obama campaign is concentrating on having lots of boots on the ground. Currently the Democrats have three times more campaign workers than the Republicans do, and they are setting up tight regional and local organizations. The Romney campaign, flush with money, has decided to concentrate its efforts instead on television ads.
See also this.