I even think that the headlong rush to homosexual marriage is a skirmish in this war.
As homosexal marriage becomes allowed in more places, attention will turn to the fact that no mainstream religion allows homosexual marriage. Eventually lawsuits will be filed against churches over the marriage issue. Mainstream religions will be in position in which they will be in violation of civil rights laws by holding to their positions on the sinful nature of homosexuality. Attempts will be made to legislate these religions out of existence.
This recent battle over birth control and Catholic organizations is another battle in this war. Liberals such as Obama see nothing wrong with forcing a liberal value on the Catholic Church. The same will eventually be done with homosexual marriage.
A: Define something as a civil right (i.e. same-sex marriage or free birth control).
B: Label anyone who disagrees a racist/bigot/sexist/homophobe/bedwetter/whatever.
C: Use the MSM propaganda ministry to incessantly reinforce the message.
This has worked the majority of the times that it has been tried. Churches are not privileged to resist or abstain. One notable exception was the ERA back in the seventies. If it had become law, the ERA would almost certainly have been used to force the Catholic Church and some protestant churches to employ women in clergy. We are again staring into the breach.