Here is how it works. Each lie is developed in the right's machine, using something currently in the news to reinforce an ongoing narrative about "liberals." The lie percolates up through a well-worn process where the germ of the story is planted in smaller outlets, and variations of it are tried out until one seems to resonate. Next, larger right-wing media operations pick up the developed "story" and drive it further. It gets amplified on the radio, FOX News and the right's newspapers. Finally the corporate media takes it out to more and more people, covering themselves with the claim they are just "reporting" on a "story" that is "already out there."
One way or another the lie is repeated and repeated and repeated (and repeated) in various forms through various channels that reach various target groups, until it becomes a "truth." Once it has become a "truth" the Romney campaign uses this "truth" to claim Democrats and President Obama are harming the country.