Christianity is the world's largest and richest religion. But Christians in many countries say they face discrimination or repression because of their faith, particularly in Islamic and communist nations. Now, activists are waging a worldwide campaign on behalf of persecuted Christians. In the United States, Christian groups are lobbying Congress to pass legislation cutting off non-humanitarian aid to countries responsible for religious persecution. But leaders of the campaign have touched off a bitter debate by accusing liberal human rights and religious groups of ignoring the mistreatment of Christians – accusations that those organizations vigorously reject. Some religious experts also dispute the claim that persecution of Christians is on the rise and complain that the campaign is ignoring mistreatment of people of other faiths.