Campaign finance experts called the decision unusual and possibly unprecedented, noting that Members of Congress do not typically register legal expense accounts in such a dual fashion.
"I guess he somehow considers the use of these legal fees, these contributions, to be political, and while they're related to political charges, typically those defense funds are not set up as 527s," said Ken Gross, a campaign finance attorney at Skadden, Arps, Slate, Meagher and Flom.
Ensign is being investigated by both the Senate ethics committee and the DOJ. He allegedly helped a former staffer find lobbying work, in violation of the one-year lobbying ban, after having an affair with the staffer's wife.
Ensign has admitted to the affair, and to having his parents give $96,000 to the couple after they left his employ.
More TPMmuckraker Ensign coverage here.