The first half of 2007 was flush for many Washington lobbying shops, particularly a half-dozen midsize firms that realized revenue between January and June that was at least double their average six-month take during the 109th Congress.

Leading the pack was Arnold & Porter, which has tripled the pace of its lobbying income this year and attributes the boon in large part to two of its newer lobbyists. One is Jim Turner, a Texan who left the House in 2005 as the top Democrat on the Homeland Security Committee but because of "revolving door" restrictions did not register to lobby until last year. The other was Matthew LaRocco, who was hired away from rival global communications firm Fleishman-Hillard, where he worked with more than two dozen clients.

"We have always seen ourselves in the upper tier of quality," says Jeffrey Smith, who oversees Arnold & Porter's government contracts and public policy group. "And now we are getting a considerable amount of volume, too." The firm has almost doubled its client roster, to 57 now from 29 in 2005.

Steptoe & Johnson boosted its business 165 percent, mainly because it's seen a 70 percent increase in its client roster. Much of the growth came with its purchase of the Scott Group, a smaller boutique firm representing financial industry interests. The firm also has recently taken on some big trade associations as clients, including the National Association of Convenience Stores, the Society of Independent Gasoline Marketers of America and the Commercial Mortgage Securities Association.

This midsize lobbying boomlet also reflects the volatile jockeying for position that accompanies the shift in party control in Congress. "There is a new sheriff in town,"says Charles M. Brain, founder of another big-gain firm, Capitol Hill Strategies. "The switch in the majority in the House and in the Senate is causing people to spend more."