Over the last two decades, more than three-fourths of Iraq’s Christians have fled the country, driven out by a combination of Muslim fanaticism and economic and social collapse. Iraq, however, isn’t the only place to experience a mass Christian exodus in recent years. Look at the Presbyterian Church (USA), the 10th largest denomination in this country. But you’d better look fast. The PC(USA), which is the nation’s largest Presbyterian denomination (at least for now), is driving out members through its own brand of leftist fanaticism. From a high of more than 4 million members back in 1965, the Louisville-based PC(USA)...