Russ Choma for Mother Jones:

The issue is that the six-year ban would only prevent former members of Congress from taking part in “official” lobbying—a very specifically defined set of activities. Avoid those activities—or earn less than 20 percent of your income from lobbying activities—and you can avoid registering as a lobbyist. There’s no shortage of high-profile ex-lawmakers who have used this loophole to sell their insider expertise and thick Rolodexes to the highest bidder without ever registering as a lobbyist. Former Democratic Sen. Tom Daschle has worked for three lobbying firms since his departure from Congress 10 years ago, never once officially registering as a lobbyist. Instead, Daschle has served as a “senior policy advisor.” Similarly, upon leaving Congress in 1999, former Republican House Speaker Newt Gingrich immediately went to work for a number of private interests offering “quasi-lobbying” services, but called his work anything but lobbying. Notably, Gingrich was paid $1.65 million for his work as a “historian” for mortgage lender Freddie Mac.