Pope Francis accepted the resignation on Tuesday of Bishop Robert W. Finn as head of the Diocese of Kansas City-St. Joseph in Missouri, heeding pleas from parishioners and priests that the bishop had lost the credibility to lead after being convicted three years ago of failing to report a priest who took pornographic pictures of girls.

It was the first time that Francis had taken action against an American bishop who neglected to protect children from pedophiles in the priesthood. Although the Vatican did not state why Bishop Finn resigned, the circumstances were clear-cut because Bishop Finn had received international notoriety as the first Roman Catholic prelate ever criminally convicted of shielding an accused priest.

Now Francis faces a much tougher call: whether he will take concrete steps to keep bishops worldwide accountable for protecting the children in their flocks from sexual abuse by clerics and church workers. In the long history of the abuse scandal, the Vatican says, it has defrocked more than 850 priests and penalized at least 2,500 more, but the matter of discipline for bishops has remained the great unfinished piece of business, and the pressure to act is only growing.

In the last month, Francis has faced bitter protests from Catholics in Chile over his decision to install Bishop Juan Barros in the Diocese of Osorno despite claims that the bishop witnessed abuse years ago and did nothing.