The sudden resignation of the most senior Roman Catholic cardinal in Britain, who stepped aside on Monday in the face of accusations that he made unwanted sexual advances toward priests years ago, showed that the taint of scandal could force a cardinal from participating in the selection of a new pope.

His exit came as at least a dozen other cardinals tarnished with accusations that they had failed to remove priests accused of sexually abusing minors were among those gathering in Rome to prepare for the conclave to select a successor to Pope Benedict XVI. There was no sign that the church’s promise to confront the sexual abuse scandal had led to direct pressure on those cardinals to exempt themselves from the conclave.

Advocates for abuse victims who were in Rome on Tuesday focused particular ire on Cardinal Roger M. Mahony, the former archbishop of Los Angeles, and called for him to be excluded from the conclave. But Cardinal Mahony, who has vigorously defended his record, was already in Rome, posting on Twitter about the weather.

Even stalwart defenders of the church point out that to disqualify Cardinal Mahony would leave many more cardinals similarly vulnerable. Many of the men who will go into the Sistine Chapel to elect a pope they hope will help the church recover from the bruising scandal of sexual abuse have themselves been blemished by it.