"Thomas was listed as a lobbyist for Freddie Mac in 2000, 2005 and 2006, according to disclosure records," writes Washington Post reporter Dan Eggen.
But does this prove, as Romney charged in Monday night's debate, that Gingrich "has worked for 15 years lobbying?
An investigation into Gingrich's work at Freddie Mac by the Politifact.com web site and others has concluded that it does.
"Experts we spoke with and the research we reviewed showed the 'strategic advice' category is a way of using influence without having to register as a lobbyist," Politifact writes in its Truth-O-Meter feature.
"There's a lot of activity that ordinary people would think of as lobbying that doesn't trigger the obligation to register as a lobbyist under federal law," attorney Joseph Sandler, a lawyer with the Washington law firm of Sandler Reiff Young & Lamb told Politifact.
"Strategic advice is one of those kinds of things that doesn't," he said.
Sandler was one of four co-chairman of an American Bar Association task force that has recommended that federal lobbying laws be changed to require that people like Gingrich who give strategic advice define their work as "lobbying support."
After digging into Gingrich's claims, Politifact reached this conclusion:
"Romney said Newt Gingrich's contract was with 'the lobbyists at Freddie Mac.' Gingrich provided strategic advice, a way of wielding political influence without having to register as a lobbyist. The primary point of contact on the contract was one of Freddie's lobbyists. We rate Romney's statement True."
And then there is this from the Center for Responsive Politics: "Newt Gingrich is certainly not alone among well-heeled political players who say they just offer consulting services or strategic advice -- without needing to register as lobbyists. But it's a stretch to claim that they aren't part of the influence game," says spokesman Michael Beckel.
Why does this matter in the fierce presidential primary battle between Romney and Gingrich for the Republican nomination?
The GOP's conservative base is searching for someone from outside of Washington to tackle the economic, debt-ridden mess that President Obama has overseen during the past three years, with little to show for it.
Gingrich, for all his political talents, is the quintessential Washington insider, peddling influence in government and then trying to wiggle out of being caught by playing word games. And that raises profound issues about Gingrich's truthfulness.
He denied he was lobbying, insisting that he was hired to be an historian, when he was selling his services to one of the richest bidders in government. He was being paid well out of Freddie Mac's coffers while it was sowing the seeds of a housing scandal that resulted in an economic meltdown that has hurt millions of Americans and cost taxpayers billions of dollars.
In other words, as a paid insider, he was part of the problem, not part of the solution.