That WSJ piece on the religious left

I've been commenting on Ms. Schmitz's thoughts on the religious left, but haven't actually gotten around to reading the Wall Street Journal piece which prompted them.  There's one passage in particular that I want to comment on:

In any event, the religious left’s sympathies do not seem to be those of churchgoers. While the NCC and its member churches pursue a variety of left-wing causes — even partnering with the activist organization MoveOn.org and featuring speakers like Michael Moore at events — a Pew poll found that 54% of white, mainline Protestants and 50% of Catholics voted Republican in the 2004 presidential elections. Those who attended church regularly voted Republican even more heavily — at nearly the same rate as evangelical Christians, in fact.

For four decades, as the leadership of America’s mainline churches has moved steadily leftward, those churches’ memberships declined as a percentage of the U.S. population while the number of Christian evangelicals exploded. Left-wing clerics may be buying greater political influence with their alliance through organized labor, but the price may be further alienating their shrinking flock.

You know, I'm not actually sure if political beliefs have anything to do with the decline in mainline congregations and the increase in conservative ones.  Christian Smith writes in American Evangelicalism: Embattled and Thriving:

In a pluralistic society, those religious groups will be relatively stronger which better possess and employ the cultural tools needed to create both clear distinction from and significant engagement and tension with other relevant outgroups, short of becoming genuinely countercultural.

In other words, evangelicalism thrives because it offers its adherents an attractive and compelling worldview that in some measure, sets itself apart from mainstream society.  It is possible that people are leaving mainline churches because they lack this engagement with and limited separation from mainstream culture.  Evangelicalism - through its emphasis on community and spreading the Gospel - is simply more compelling than mainline Protestantism, and the latter is suffering as a result.