WASHINGTON, Feb. 1 - House Republicans headed toward a defining leadership election on Thursday with their membership sharply split over how much to shake up the leadership ranks and how to respond to a politically charged lobbying scandal.

In a prelude to the selection of a new majority leader, Republicans on Wednesday rejected a call to open all seven leadership slots below Speaker J. Dennis Hastert to challenge. But the 107-to-85 vote in an extended closed-door party meeting was evidence of strong discontent among the rank and file in the aftermath of the scandal, a contrast to the discipline and unity that has been a hallmark of House Republicans.

"I think it sends a message to all, leadership and conference members alike, that there is a serious issue we need to face," said Representative Dan Lungren of California, who joined with Representative John E. Sweeney of New York in the unsuccessful push for broader elections.

At the same time, the Republican leadership ran into resistance in its first effort to tighten lobbying rules in response to bribery cases involving the lobbyist Jack Abramoff and former Representative Randy Cunningham of California. While the House ultimately voted 379 to 50 to ban former-lawmakers-turned-lobbyists from the floor and the members-only gym, members of both parties derided the plan as unnecessary and woefully insufficient.