I believe that narby's concern is the same as mine. Contrary to what you might think by observing the behavior of people on sites like FR and DU, the vast majority of the voting public are neither committed conservatives nor committed liberals, but rather hold to some mushy centrist-type beliefs. If the liberals do succeed as painting conservatives as anti-science theocratic luddites, due to the vehemence with which they fight for the teaching of creationism, then many people who are in this mushy center will be turned off by conservatives and will vote in greater numbers for liberals. Considering that literal Biblical interpretation and belief in creationism are NOT central tenets to the conservative movement, it would seem logical that we should abandon this fight and concentrate on things that are central to our common beliefs, such as lower taxes, smaller government, abolishment of Roe v. Wade, etc.
Good summary in #409