For six years, Doug Stafford was a lobbyist for the National Right to Work Committee, an anti-labor group financed by business and conservative interests. His job changed last year but his duties did not when he became the chief of staff to Senator Rand Paul, Republican of Kentucky. Mr. Paul is a chief sponsor of the National Right to Work Act, which he said would end forced unionization and “break Big Labor’s multibillion-dollar political machine forever.”

Brett Loper’s career path is a similar one. When he was an executive for the Advanced Medical Technology Association, an industry group, he lobbied hard against President Obama’s health care reform. Now, as the chief policy adviser for Speaker John Boehner, he is helping to organize the effort to repeal the health care law. The only difference is that the taxpayers are paying his salary.

There has long been a regular shuttle service between Capitol Hill and Washington’s K Street, but the numbers now are striking. Since last year’s Republican victories, nearly 100 lawmakers have hired former lobbyists as their chiefs of staff or legislative directors, according to data compiled by two watchdog groups, the Center for Responsive Politics and Remapping Debate. That is more than twice as many as in the previous two years.

In that same period, 40 lobbyists have been hired as staff members of Congressional committees and subcommittees, the boiler rooms where legislation is drafted. That again dwarfs the number from the previous two years.

While some of those lobbyist-staffers were hired by Democrats, the vast majority are working for Republicans. Representative Raul Labrador, a freshman from Idaho, hired John Goodwin, previously a lobbyist for the National Rifle Association, as his chief of staff. Representative Fred Upton, chairman of the Energy and Commerce Committee, hired Howard Cohen, a longtime lobbyist for the health care industry, as his chief counsel.

In many cases, those hiring lobbyists were Tea Party candidates who vowed to end business as usual in Washington. As The Washington Post reported, when Ron Johnson ran against Wisconsin’s Senator Russ Feingold, he accused Mr. Feingold of being “on the side of special interests and lobbyists.” Now that he is a senator, Mr. Johnson has hired as his chief of staff Donald Kent, whose firms have lobbied for casinos, defense industries and homeland security companies.

Ethics laws put limits on elected officials who move to lobbying firms. But there is nothing to stop lobbyists from getting immediately hired on Capitol Hill. This year’s class of staffers argues for a tough ban. After collecting millions from industries or unions or others, lobbyists should not be allowed to turn around and write laws that favor these special interests.