At a breakfast fund-raiser last year at the Liaison Capitol Hill hotel, former lobbyist Paul Equale pulled up a chair next to Sen. Richard Durbin. As they chatted, the Illinois Democrat told him about a recent breakthrough in his efforts to push through a bill to cap debit-card fees. At a breakfast fund-raiser last year at the Liaison Capitol Hill hotel, former lobbyist Paul Equale pulled up a chair next to Sen. Richard Durbin. As they chatted, the Illinois Democrat told him about a recent breakthrough in his efforts to push through a bill to cap debit-card fees. Some investment...