Viral emails have emerged as a form of stealth propaganda recently, most noticeably in the recent U.S. presidential campaign, when Barack Obama was dogged with false claims that he was a Muslim, that he was refused to salute the American flag, that he was not a U.S. citizen and so forth. The Washington Post reported earlier this year that Danielle Allen, a professor at the Institute for Advanced Study in Princeton, New Jersey, attempted to trace the chain of one of those emails and found what the Washington Post called "valuable insight into the way political information circulates, mutates and sometimes devastates in the digital age." She noted that the anonymous nature of viral emails, combined with the word-of-mouth way that they spread, makes them hard to counter. "This kind of misinformation campaign short-circuits judgment," she said. "It also aggressively disregards the fundamental principle of free societies that one be able to debate one's accusers."