If you follow religion news closely (which would make you the kind of person who frequents this website), then you know that there are two major, overarching trends taking place in modern America that are affecting all kinds of religious organizations.

This is certainly true in Christianity and also in Judaism. The same trends may be affecting Muslims and members of other major world religions, but I am not sure -- in part because I have not seen enough research in those communities.

The first major trend -- which has generated massive amounts of coverage -- is the rapidly rising tide of Americans identifying themselves as "religiously unaffiliated," meaning that they claim no ties to any particular religious tradition. Yes, these are the "Nones." This does not mean that they are pure secularists, although many are (while some are "spiritual but not religious"). The stats for atheists and agnostics are on the rise, as well.

The second trend, in tension with the first, is that the large slice of the American population that practices traditional forms of religious faith does not appear to be declining, or not at a rapid rate. True, some of these believers have been switching from one sanctuary to another.

It is also significant, in terms of demographics, that people in more doctrinally conservative forms of faith tend to (a) have more children and (b) take part in efforts to win converts to their faith. See, for example, the numbers for Pentecostal Christians and the Church of Jesus Christ of Latter-day Saints. Compare the birth rates for Orthodox and Reform Jews.

What is shrinking is the "mushy middle" of the spectrum, the lukewarm believers and those in faiths that make weaker demands on their time and convictions. Yes, this same theme showed up in that recent flurry of online discussions about the future of the religious left.

This brings us to a trend that researchers have been discussing for nearly 50 years -- the statistical decline of the "seven sisters" denominations in old-line Protestantism. And that, in turn, brings us to this weekend's think piece on a topic close to the religion beat -- an "Acts of Faith" essay in The Washington Post by Ed Stetzer, the executive director of the Billy Graham Center at Wheaton College. 

The headline is a grabber: "If it doesn’t stem its decline, mainline Protestantism has just 23 Easters left."