The United States is becoming less religious, a development driven mostly by declining numbers of Catholics and Protestants. The change is notable because it crosses demographic, geographic and economic lines. In addition, the number of people who identify themselves as not religiously affiliated — the “nones” — is on the rise. Islam is growing rapidly worldwide, largely because of Muslims’ soaring birth rates and comparatively young population. American Muslims make up 0.9 percent of the U.S. population, up from 0.4 percent seven years ago. If global trends continue, the world’s Muslim and Christian populations will be about equal by 2050. Meanwhile, U.S. states are grappling with “religious liberty” issues. And internationally, Pope Francis is making waves among Catholics and non-Catholics alike as he speaks out on a number of controversial issues.