The returns from the Super Tuesday primaries could signal the end of the race between Texas Gov. George W. Bush and Arizona Sen. John McCain. But for Republican lobbyists, the fallout from the unexpectedly rancorous nomination contest may be just beginning.

Over the last year, scores of Washington’s advocates-for-hire have put their fund-raising muscle behind either the front-running governor or the sitting chairman of the powerful Commerce, Science, and Transportation Committee. It has turned out to be a high-stakes gamble.