Our results indicate that this sort of journalistic fact-checking often fails to reduce misperceptions among ideological or partisan voters. In some cases, we found that corrections can even make misperceptions worse. For example, in one experiment we found that the proportion of conservatives who believed that President George W. Bush’s tax cuts actually increased federal revenue grew from 36 percent to 67 percent when they were provided with evidence against this claim. People seem to argue so vehemently against the corrective information that they end up strengthening the misperception in their own minds.A pdf of the actual research is here, if you'd like to read the set of experiments that explored this partisan insistence toward non-knowledge (for lack of a better term).
I roam the same theoretical turf. The Journal of Media and Religion will publish soon my study on who the people were who insisted at multiple times during the 2008 election that Obama was Muslim. While the journal article isn't published yet, you can beat the rush and read about it here in my local daily or by the NYTimes here.
The point is, partisanship drives not only selective attention, exposure, and retention of information, but counterarguing even a fact-check that corrects the misperception can lead to even more incorrect knowledge. It's a fascinating area, sort of reverse political knowledge, and the ultimate lesson from my study -- and others -- seems to be that nothing journalists or fact-checking web sites can do will correct people's misperceptions, especially when they're wingnuts.