It’s pretty self-evident that Newt Gingrich lobbied on behalf of Freddie Mac, despite his repeated denials during the past few months. The former speaker prefers to use euphemisms like “historian” and “consultant” to describe his work, but he slipped up during a blistering exchange with Mitt Romney, and appeared to finally fess up to lobbying. BuzzFeed reports:

Tonight in Tampa, Newt Gingrich offered what he seemed to think was ironclad proof that he had never been a lobbyist: “We brought in an expert on lobbying law and trained all of our staff.”

That expert, he added, would “testify” to that point.

But to be forced to register under the federal Lobbying Disclosure Act and to lobby aren’t the same thing. The LDA merely requires that anyone who spends more than 20 percent of his or her time on “lobbying activities” register.

Gingrich added that the expert taught the staff how to avoid crossing the “bright line,” an apparent reference to the 20 percent mark. If Gingrich’s firm hadn’t been engaged in any lobbying activities whatsoever, it wouldn’t need to have an expert come in and explain how to conform to lobbying rules (which are laxly enforced as it is).

Romney may not have had any knockout punches against Newt last night, but the former speaker handed him a lot of ammo for the next few days with that answer.