Evangelicals have identified their movement with the culture war and with political conservatism. This will prove to be a very costly mistake. Evangelicals will increasingly be seen as a threat to cultural progress. Public leaders will consider us bad for America, bad for education, bad for children, and bad for society.
The evangelical investment in moral, social, and political issues has depleted our resources and exposed our weaknesses. Being against gay marriage and being rhetorically pro-life will not make up for the fact that massive majorities of Evangelicals can't articulate the Gospel with any coherence. We fell for the trap of believing in a cause more than a faith.
Now I'll admit that Spencer goes off the rails when he additionally suggests that wide-spread intolerance of Christians will also result, but the conservative evangelicals have always had a bit of persecution complex. However, the article is well worth your while and is overall a pretty thoughtful piece of self-examination. You'll want to check out the commentary in Rod Dreher's section of Beliefnet as well. Another conservative Christian who, even though I have plenty to argue with him about, has lately been taking a hard look at their role in the culture wars.