The reception thrown by Nancy Pelosi at the Capitol a week after the Democrats prevailed in congressional elections was a party some power players had been waiting more than a decade to attend. The fĂȘte was for newly elected freshmen lawmakers, but Pelosi's invited guests included big-name Democratic lobbyists like Jack Quinn, Tony Podesta and Steve Elmendorf. Said a partygoer: "I thought to myself, they're all back, all the same old faces. It was just like old times."
For 12 years, Democratic lobbyists lost influence--and money--as Republicans tightened their hold on power. G.O.P. leaders amplified the effect by launching an overt...