Federal law bans not only the casting of, but the "procurement" of ballots "that are known by the person to be materially false, fictitious, or fraudulent under the laws of the State in which the election is held."
Hamline University law professor David Schultz told TPM that there's "no doubt" that O'Keefe's investigators violated the law.
"In either case, if they were intentionally going in and trying to fraudulently obtain a ballot, they violated the law," Schultz said. "So right off the bat, what they did violated the law."
Election law expert Rick Hasen, who writes the Election Law Blog, joked in an email to TPM that O'Keefe's team should "next show how easy it is to rob a bank with a plastic gun."
"Who in their right mind would risk a felony conviction for this? And who would be able to do this in large enough numbers to (1) affect the outcome of the election and (2) remain undetected?" Hasen wrote.
Other election experts agreed that the video doesn't change the substance of the debate over whether the minimal threat of in-person voter fraud is worth the impact that such laws can have on minority and poor voters.
"The fact that activists can engage in a stunt is not a reason for reform," Samuel Issacharoff, a professor of constitutional law at New York University Law School, told TPM. "It means nothing. Why would anybody want to do this? It proves that they don't update their dead voter information as quickly as they might, but so what? To pull this off on a large scale, you'd need coordination, and presumably somebody would have heard about it."
Someone did, in fact, catch on to the scheme when a man dressed in a suit and tie tried to vote as a dead man known to the poll watcher. The man left before police arrived and said the poll watcher would "soon find out" why he tried to vote under a fake name, the Boston Herald reported Tuesday night.
Henry Brady of the University of California told TPM that O'Keefe's video showed that what his team did was "possible" but said that was never really a question. He also said that other techniques short of voter ID -- like asking voters to sign a roll when they receive their ballot -- would stop the type of fraud O'Keefe's allies were attempting.
"Yes, this shows it's possible to do what they did but you have to ask yourself... how many illegal immigrants would risk a jail term to vote illegally?" Brady said. "What they didn't tell us, were they ever stopped and asked what's going on here."
John Samples of Cato told TPM that this would be a political issue and that O'Keefe was "pushing on an open door" because voter ID is politically popular. But he questioned whether it was worth the risk for O'Keefe.
"This is illegal, right? This is fraud and you would think he would actually get into trouble for doing this," Samples told TPM.
Samples said that O'Keefe's video could have an impact in the political fight over voter ID laws but "in the judicial fights -- and the fight amongst wonks -- it wouldn't change much. The big question for policy always was what was the extent of it, and this doesn't solve that question."
The video, first obtained by the Daily Caller, is embedded below.
Late update: Richard Head of the New Hampshire Attorney General's office issued this statement to TPM: "We became aware of the issue yesterday on election day, and immediately began conducting an investigation. In addition, based upon the information we received yesterday and the information in the video, we've initiated a comprehensive review of voting procedures with the Secretary of State."