VATICAN CITY – Pope Francis vowed Monday that “no effort must be spared” to root out priestly sex abuse and cover-up from the Catholic Church, but gave no indication that he would take action to sanction complicit bishops or end the Vatican culture of secrecy that has allowed the crisis to fester. In a letter to Catholics worldwide after damning new revelations of misconduct in the U.S., Francis sought to project a get-tough response to the perpetrators and a compassionate shoulder for victims ahead of a fraught trip to Ireland this weekend. Francis begged forgiveness for the pain suffered by victims and said lay Catholics must be included in the effort to root out abuse and cover-up.