The anonymous congressional staff members who write the nation’s laws generally work hard for fairly modest wages. Increasingly, though, they do so because there is a promise of K-Street riches at the end of their toil.

A new study by the Sunlight Foundation found that the number of active lobbyists with prior government experience has nearly quadrupled since 1998, rising to 1,846 in 2012. Those revolving-door lobbyists, mostly from Capitol Hill, accounted for nearly all of the huge growth in lobbying revenue during that period, which increased to $1.32 billion from $703 million in 1998.

A New York Times article on Sunday showed that many of those former staff members are violating the intent of a 2007 law that requires a waiting period before former congressional employees can lobby Congress. The law imposes a one-year ban for senior staff and House members, and two years for senators, but some House staff members are deliberately keeping their salaries low so they won’t be considered “senior” and can lobby right away. Others use a loophole to claim that they can lobby a committee right away, because they technically worked for an individual lawmaker and not the committee.

Some of those who are lobbying or working for corporate clients are actually former lawmakers. Joe Baca, a former Democratic congressman from California, introduced a bill when he was in the House that would have reduced oversight of payday lenders, notorious for exploiting desperate low-income people. Then, after he left the House, the payday lending industry hired him to run its lobbying organization. (He is now running for re-election, adding gall to his spin through the door.)

Cliff Stearns, a Florida Republican who spent 20 years on the House Energy and Commerce Committee, is now working for APCO Worldwide, a large lobbying firm, where he advises clients on telecommunications and trade. Mr. Stearns should know a lot about the subject, since he was the ranking member on the telecommunications subcommittee, where he helped big corporations in that field try to kill net neutrality, which would have allowed phone and cable companies to undermine the open nature of the Internet and give special treatment to some services.

But most of the revolvers are staff members, particularly those who worked on important committees. Jim Coon, who was Republican staff director for the House Transportation and Infrastructure Committee, is now senior vice president for government affairs and advocacy at the Aircraft Owners and Pilots Association. He has also worked for Boeing and the National Air Transportation Association.

Many law firms and lobbying shops have no qualms about impressing their clients with the government experience of their revolving-door staff. Clarine Nardi Riddle, who was chief of staff to former Senator Joseph Lieberman, “draws on her insider’s perspective of the legislative and judicial systems to provide legal, strategic and policy advice to national and international clients on matters at the intersection of law, business and public policy,” according to the website of her current employer, the law firm Kasowitz, Benson, Torres & Friedman. Not coincidentally, Mr. Lieberman works there, too.

The danger of this practice, as always, is that the lure of corporate-lobbying money is strong enough to orient both lawmakers and their staffs toward the values of their future employers. (And it’s not necessary to be a registered lobbyist to make big money in the influence game.) This isn’t a new phenomenon, but its growth shows that the current waiting period before congressional employees can lobby is far too easy to evade, and may not be long enough.