There is still a lot of confusion about what McDonnell is likely to be charged with. This is in no small part due to a partially successful public relations campaign ran by McDonnell to create confusion about Virginia's ethics laws and federal anti-corruption laws. McDonnell's PR pushed the line that McDonnell broke no Virginia ethics laws and therefore should not be prosecuted by federal authorities. Many reporters picked up this line of argument and reported it, further spreading the confusion and disinformation. If Bob McDonnell is to be charged with anything, he will likely be charged under the Hobbs Act.
The Hobbs Act, enacted in 1946, was named after Congressman Sam Hobbs (D-AL). The act is part of the federal code at 18 U.S.C. § 1951. The Hobbs Act imposes a stiff penalty for certain kinds of behavior:
(a) Whoever in any way or degree obstructs, delays, or affects commerce or the movement of any article or commodity in commerce, by robbery or extortion or attempts or conspires so to do, or commits or threatens physical violence to any person or property in furtherance of a plan or purpose to do anything in violation of this section shall be fined under this title or imprisoned not more than twenty years, or both.While the Hobbs Act was originally intended to combat racketeering, it has been applied widely to punish extortion by public officials. The Hobbs Act makes use of Congress' power to regulate interstate commerce via the Commerce Clause. The Hobbs Act covers extortionate acts by state and local public officials acting under the color of right. A public official--oh, just hypothetically, let's say a state governor--commits extortion under the color of right when he obtains a payment to which he is not entitled knowing that it was made in exchange for official acts--like, and I'm just kind of spitballing here, allowing the company to use the Governor's Mansion for a launch party and arranging a meeting with the Virginia Department of Health and Human Resources--stuff like that.
It's seems kind of farcical to me that someone would have such elaborate rationalizations for evading Virginia's barely there ethics laws in regard to "gifts" to elected officials while at the same time paying no attention to the implications of the Hobbs Act. But McDonnell wasn't the only Virginia official to make this mistake; in his efforts to avoid prosecution for violation of Virginia's ethics laws, Ken Cuccinelli may have inadvertently admitted to violating the Hobbs Act himself.