The new media environment raises two questions: Will campaign deceptions have traveled around the web before journalism has the fact-checking in place to ensnare them? And if diligent checking of claims does exist, will it fall on an audience too enmeshed in its own biases to see past them? This essay draws on evidence from the Annenberg Public Policy Center’s 2012 Institutions of Democracy Political Knowledge Survey to argue that long-form political fact-checking can increase the accuracy of voters’ perceptions of both candidate stands on issues and the background facts of the presidential race.