At its core, the indictment alleges that Edwards knowingly: 1) in violation of federal campaign finance law, accepted money well in excess of the individual campaign contribution limits; 2) spent that money to hide his extramarital affair with Rielle Hunter; and 3) in violation of federal campaign finance law, failed to disclose either the donations or the expenditures. Edwards does not appear to contest number 2), which is not, in and of itself, illegal. Instead, his defense appears to be that, with respect to 1), the hundreds of thousands of dollars provided by Fred and "Bunny" Mellon were personal gifts, and that with respect to 3), the money spent to hide l'affaire Hunter was a personal expense rather than a campaign expenditure that needed to be disclosed.
Assuming the facts alleged can be proven, the government's argument with respect to 1) is very strong. Last week, the Huffington Post and Paul Caron both suggested that Bunny Mellon's gift tax return could help Edwards. Apparently, she filed a return listing a $700,000 personal gift to Edwards. This supposedly shows that the money was intended as a gift rather than as an unlawful campaign contribution. With due respect, it shows no such thing. Unless Mellon gave Edwards the $700,000 in cash (perhaps fourteen $50,000 bills?), a transaction that large would have called attention to itself, and thus would have to be characterized in some way. If, as the government alleges, this was all a big conspiracy to evade campaign finance laws, then calling it a gift was part of the conspiracy, not a defense to it.