Conservative churches grow... liberal ones die...

Conservative churches are not growing because they are conservative.  Liberal churches are not dying because they are not conservative.  It is the nature of liberality that it does not require nor does it compel one to join.  One can merely agree not to challenge as well as fundamentally agree with liberalism and that is enough.  The primary virtue of liberalism is tolerance -- not that the liberals tolerate all but that all tolerate liberal ideas.  Such assent does not require union or participation and can be enjoyed at a distance without requiring affiliation.

Conservative churches grow because they believe it is essential to belong and to attend and to support.  Yes, they challenge all that contradicts what they believe, they encounter all people with their cherished beliefs, and insist their truth is true for all people but this is not something the lives merely in the imagination.  It is a way of life.  Conservative churches are generally organized around their beliefs -- beliefs held not for the sake of the few but in trust for all.  It is the holy calling of conservative churches to make sure that all know and receive what it is that they hold in trust for the sake of all.

Liberal Muslims like liberal Christians seem to be a dying breed.  They seem unable to muster the confidence or courage to suggest that their truth must be held by all, that it is worth the fuss of conversion, or that it is worth the investment of attendance.  They merely want to be tolerated.  They extend their influence not by adherents so much as by consent.  Their nature is not so much fervor as it is intellectual agreement, a liberal view of life that they extend to Christianity and not a Christian view that they extend to their liberalism.

Conservative Muslims and conservative Christians are not content to sit on their hands while people disagree.  Both have a missionary purpose and goal.  They want all to believe as they believe and to live as they live.  Now, to be sure, I am not at all equating Islam and Christianity.  There is a wide world of difference between conservative Christians and Muslims in what is believed and confessed.  Islam seems uncontent with the idea that people can disagree without consequence and are enforcers of their orthodoxy.  Even sectarian Christian groups can be militant (think in the past of Westboro Baptist Church) -- though nearly all without taking up arms as the radical Muslims have done.  Most conservative Christians believe that God will deal with those who have rejected the truth and that their cause is to give witness to the Gospel.  Unlike the Islam who act to enforce God's judgment, the conservative Christians act to preserve the faith and to proclaim it for the sake of all who will sit under God's final judgment.

There is a huge group of Christians who are conservative in faith, doctrine, and practice, but who speak of those who reject the truth less in terms of retribution than loss.  Roman Catholics, Orthodox, and Confessional Lutherans are intentional in their faith.  They all believe that they hold in trust the evangelical and catholic faith of the Apostles.  But their missionary import is inclusive.  They have what God intends for all, not simply as a refuge from the terror but as the positive gift of peace, life, and hope.  Rome insists that there is no salvation outside of the Church but by the Church they mean Rome.  Orthodoxy is perhaps more generous but likewise has a narrow view of communion all the while expecting its truth is not for the few.  Confessional Lutherans believe that what we espouse in our Concordia is not our own version of the faith but the truth confessed for the sake of all.  My point is not to parse the conflicts between Rome, Constantinople, and Wittenberg but to illustrate how they understand their role and purpose as guardians of the truth for all not to condemn but to preserve. 

Liberalism is not simply an aspect of Christianity.  The same tolerance they insist upon for doctrine and practice is itself the principle for all of life -- except when it comes to tolerating conservative dissent.  They insist upon a tolerance which accepts nearly all the diversity liberalism espouses but refuses to condone the narrowness of the conservative.  Oddly enough, this is somewhat personal.  There is a strange willingness to be more charitable toward the Muslim conservative than the Christian.  It is, of course, their own discomfort with the whole of Christian history and the whole idea that Christianity has been a force for good.  They not only disown individual doctrines of the Christian faith but Christian history and influence over culture and life as a whole.  Liberal churches are less united in their affirmation of what they believe but in their condemnation of what they reject.  In essence, there is little reason to join a liberal group since you can reject nearly everything and accept everything else without the bother of joining.  In other words, liberals have yet to develop and apply a compelling reason for joining anything.  As an example, when was the last time you saw the parking lot full at a Unitarian Universalist congregation?