Secularism seems to be on the march in America. This week, a new study from the Program on Public Values at Trinity College found that the number of Americans claiming no religion now stands at 15%, up from 8% in 1990 and 2% in 1962.

The secular tide appears to be running strongest among young Americans. Religious attendance among those 21 to 45 years old is at its lowest level in decades, according to Princeton sociologist Robert Wuthnow. Only 25% of young adults now attend services regularly, compared with about one-third...