The other prosecutorial shoe has finally dropped on Robert McDonnell, Virginia’s just-retired Republican governor. Last week a federal grand jury indicted the former governor and his wife, Maureen, for conspiring to defraud Virginia’s citizens of McDonnell’s “honest services” and to obtain property “under color of official right” — that is, to procure bribes through extortion. He was also charged with making false statements and obstructing an official investigation.

The indictment is replete with details of the many gifts the McDonnells received from Jonnie Williams, a corporate executive who was trying to get state help for his company.

But the governor’s defenders are now describing the whole affair as an unfortunate lapse in the first lady’s judgment. They note that McDonnell rejected a deal proposed by prosecutors, in which the governor would plead guilty to a single felony charge unrelated to official corruption and his wife would escape prosecution altogether. In other words, these defenders suggest, the prosecutors are not so confident of the strength of their case.

The key question is: Do the facts of the case add up to an unambiguous crime? If so, what crime?

It’s anyone’s guess.

“Theft of honest services” cases have become more problematic since the Supreme Court recently ruled they should only apply to actual bribery and kickback schemes — not to simple self-dealing or conflict of interest. In addition, without evidence of what is called “extortionate duress,” an imposition of a real fear of harm, a court in a bribery case is now more likely to require a concrete example of an official delivering some “public good” in exchange for the property received.