From the Washington Post:
The federal Centers for Disease Control and Prevention recently issued a flier to combat myths about the flu vaccine. It recited various commonly held views and labeled them either "true" or "false." Among those identified as false were statements such as "The side effects are worse than the flu" and "Only older people need flu vaccine."
When University of Michigan social psychologist Norbert Schwarz had volunteers read the CDC flier, however, he found that within 30 minutes, older people misremembered 28 percent of the false statements as true. Three days later, they remembered 40 percent of the myths as factual.
Younger people did better at first, but three days later they made as many errors as older people did after 30 minutes. Most troubling was that people of all ages now felt that the source of their false beliefs was the respected CDC.
Extend this to politics, and indeed the mantra of 'Who cares about facts or truth, all that matters is what people think' does indeed make good sense. (Not that research is really needed to discover that such an approach works.)
Politics aside, though, it's an interesting thing to consider. I remember from somewhere that if you want someone not to do something, it's better to use a positive sentence with a 'negative' verb, rather than a negative sentence with a 'positive' verb. (Example: 'Leave that cup on the counter' will tend to work better in the long run than 'Don't move that cup off the counter'). <shrug> Makes pretty good sense to me...