The lawyer who a decade ago advised Newt Gingrich on how to engage in advocacy without officially becoming a “lobbyist” is now working to close the loopholes that enable the former Speaker and other Members to avoid public disclosure.

Gingrich argued in a GOP debate Monday night that he was never a lobbyist, which is true largely because the lobbying rules allow individuals to conduct limited advocacy activities without being legally required to register.

Gingrich said he had hired “an expert in lobbying law” to make sure he never did anything that would qualify him as a lobbyist.

That expert was Thomas Susman, now the director of governmental affairs at the American Bar Association, which is pushing to expand the lobbying disclosure rules so that advocacy professionals don’t fly under the radar as Gingrich did.

“In the year 2000, Mr. Gingrich said: ‘I’m going to have consulting, strategizing — whatever it is — take me around the country, and I don’t ever want to cross the line and register as a lobbyist,’” said Susman, who at that time was a lawyer with Ropes & Gray. “And that’s what I was hired to do.”

Susman confirmed that he trained staff members at Gingrich’s firm, then known as the Gingrich Group. He declined to go into the details of his advice to Gingrich but said the definition of a federal lobbyist is clear: someone who spends at least 20 percent of his time for each client on lobbying activity and also makes two contacts with covered government officials.

“There is a clear line at 20 percent,” Susman said. “At 19 percent, even if you get $100,000 for your advice, you’re not required to register under federal law. It’s fairly clean.”

But things are trickier than they look, say experts familiar with the Lobbying Disclosure Act. Lobbying activity includes the typical K Street work such as asking a Member of Congress to vote for a bill. But it also includes behind-the-scenes strategy sessions with colleagues and clients to prepare for meetings or contacts with covered officials.

“If an in-house lobbyist is going to be speaking with somebody on the Hill and says, ‘Do you know this guy? What’s the best way to approach him?’ And you help him prepare, that’s lobbying,” explained Ken Gross, a partner at Skadden, Arps, Slate, Meagher & Flom who specializes in lobbying laws and ethics.

And it’s much easier to trigger a lobbying contact than one might think, Gross said. Calling a Congressional aide to set up a meeting or urging the staffer to take a client’s phone call is, in most cases, a lobbying contact. Even being present — but not speaking — during a client’s meeting on Capitol Hill is a lobbying contact, he added.

“People say to me, ‘I don’t lobby. I engage in strategic planning and education,’” he said. “I say to them, ‘That’s exactly what lobbying is — if it’s for the purpose of influencing legislation or policy, not strategic planning on who’s going to win the Super Bowl.’”

Added William Minor, a lobbying expert at DLA Piper: “There is confusion about the 20 percent. They think, ‘I only made a couple of phone calls, it took an hour.’ But the question is always 20 percent of your time for that client. What else did you do unrelated to lobbying activity for that client?”

The 20 percent cutoff is precisely one of the reasons the ABA is lobbying for an expanded definition of lobbying, Susman said. In August, the ABA approved a resolution that would expand lobbying disclosure and registration rules and require a two-year cooling-off period for lobbyists making campaign contributions.

“Our feeling is the lobbying disclosure law is not capturing the full picture of money being paid to influence official decision-making,” Susman said. The ABA resolution calls on Congress to require LDA registrants and their clients to report “lobbying support activities” by the firms they retain, “including strategy, polling, coalition building and public relations activities.”

Howard Marlowe, a registered lobbyist who is president of the American League of Lobbyists, said his organization also plans to release a proposal in March that would “close the Gingrich loophole.”

Marlowe said many K Streeters operate in the shadows even if, in reality, their work meets the two-contact, 20 percent threshold.

“You can do it because there’s no enforcement. Nobody’s gonna find you,” he said. “We think anybody who is doing advocacy work — and getting paid — ought to be transparent to the public.”

It’s precisely the kind of influence consulting that’s stirred up controversies over the advocacy work of former lawmakers such as ex-Sens. Bob Dole (R-Kan.) and Tom Daschle (D-S.D.). Dole initially denied being a lobbyist but eventually registered as one.

Daschle signed on as a “special policy adviser” with the K Street shop of Alston & Bird, an ambiguous and controversial role that helped knock him out of the running to be Health and Human Services secretary when President Barack Obama took office.

For his part, Gingrich has forcefully denied Romney’s attempts to paint him as a K Street “influence-peddler,” saying flatly during the Monday debate: “I have never done any lobbying.” But three former Members of Congress and one sitting House Member have told various news outlets that Gingrich contacted them in 2003 to urge them to vote for a bill that expanded prescription drug benefits for Medicare recipients.

The watchdog group Citizens for Responsibility and Ethics in Washington has called for a federal investigation into whether Gingrich violated the Lobbying Disclosure Act.

“Mr. Gingrich was a lobbyist, and he should not be allowed to play word games with the American people,” CREW Executive Director Melanie Sloan said in a statement.

The Gingrich campaign did not respond to email requests for comment on this article.