The highly loaded term "culture war" generally refers to conflict, within U.S. society and politics, between religion-oriented conservatives and emerging humanist values. It reflects cultural divides in the United States which predate the U.S. Civil War such as religious divisions that started to develop during the Second Great Awakening.
The term carries echoes of the Kulturkampf (literally, "culture struggle" or "culture fight"), largely against Catholicism on behalf of the Evangelische Kirche (literally, "Evangelical Church", more familiarly, the state Lutheran church) , in the 1800s German Empire under Chancellor Count Bismark.
As it is used by many people in the United States, this term is not value neutral. It commonly carries with it the unspoken assumption that existing values and/or values favored by the speaker are under attack by the adherents of "un-American" cultures. Non-Christian (not to mention anti-Christian) value systems, humanist value systems, value systems condoning or approving of homosexual relationships, etc., are viewed as having in effect "declared war on" the traditional values. American culture is sometimes upheld using the term:culture of life which is inherited from modern Catholicism under John Paul II.
Underlying the idea of "culture wars" or the assertion that one set of priorities upholds "life" more than others is the more fundamental claim that certain individuals have the right and power to tell others what they are required to believe. These claims can be seen very clearly in the recurrent attempts to make Biblical accounts of the creation take precedence over the explanations that are grounded on evidence and analysis. Or that the "rights" of the unborn are important but there is no right to housing or food once born.