Let's begin with an unassailable fact: John Edwards behaved very badly.
He cheated on his wife, Elizabeth Edwards, who was suffering from a debilitating cancer that eventually killed her. He repeatedly lied about his affair with photographer Rielle Hunter, including on national television. He got one of his key aides, Andrew Young, to falsely claim he was the father of Edwards and Hunter's baby. He used donations from wealthy political supporters, Bunny Mellon and Fred Baron, both to support his lavish affair (including private jets to California and stays at the Four Seasons in Santa Barbara) and to support his mistress and baby after the child was born.
What's less clear, however, is whether Edwards should go to jail for his behavior. Specifically, does it amount to a violation of federal campaign-finance laws?
The indictment against Edwards is sordid and lays out the campaign-finance charges. Describing Edwards' "public image as a devoted family man" as the "centerpiece" of his 2008 presidential campaign, it notes that federal law at the time prohibited individuals from donating more than $2,300 to Edwards in the primary. Mellon and Baron allegedly gave much more—apparently more than $900,000—to benefit the campaign and Edwards' family-man image. Edwards took contributions in excess of what federal law allowed, conspired with others to do so, and lied about it by not including the contributions on forms filed with the Federal Election Commission.
The problem with this theory is that it is not clear that these expenses fit the legal definition of a "contribution." As the indictment explains, that definition includes "anything of value provided for the purpose of influencing the presidential election," including contributions to a candidate. But it does not include payments for the personal expenses of a candidate if "they would have been made irrespective of the candidacy."
If Edwards took the cover-up money to save his marriage and generally preserve his public image, he's not guilty of federal campaign-finance violations. That's why the indictment emphasizes the "devoted family man" aspect of the campaign. So the question is how to draw the line between the personal and the political.
Lines like this are drawn in the campaign-finance world all the time, and usually they come up in civil proceedings before the Federal Election Commission. There's a civil complaint pending at the FEC against former Delaware Senate candidate Christine O'Donnell, for example, for using campaign funds for personal use, like rent for her apartment.
If the Edwards matter came before the FEC as a civil complaint, it is not clear how it would rule. There are conflicting FEC opinions in similar cases. In 2000, the FEC issued an advisory opinion saying that the only way a gift to a candidate could be considered personal and not an illegal contribution motivated to help the campaign would be if there was a pattern of gift-giving before the candidacy. Yet in 2002, the FEC dismissed a complaint against Rep. Jim Moran, who had gotten a $25,000 loan from a drug lobbyist, because the loan was not used for campaign purposes. The complaint alleged the loan was an illegal campaign contribution, but Moran signed the check from his lobbyist friend over to pay his divorce lawyer. In the Edwards case, the parties have been throwing around these conflicting precedents to support their case.
But this is not a civil complaint. It's a criminal indictment. It's going to be tough to prove beyond a reasonable doubt that Edwards was taking this money to save his campaign rather than his marriage. (In the end, of course, neither survived.) Politico reports that the prosecution has been looking around for former FEC commissioners to testify about how to interpret the campaign-finance law, and at least one of these commissioners has turned the government down, viewing the case as too murky.
If the law is so murky that the government needs an expert to testify as to what it actually means, there's a decent argument that it would be unconstitutional to use that law as the basis for a criminal prosecution. It is just too vague. (The government might have a better case against Mellon. According to the indictment, Mellon, incensed about a furor over Edwards' expensive haircut, sent a note to Andrew Young saying that "from now on, all haircuts, etc., that are necessary and important for the campaign—please send the bills to me. … It is a way to help our friends without government restrictions.")