I've always thought the biggest threat to religious liberties in the United States will come from homosexual activists and associated sexual lifestyle groups. It will come initially through the use of anti-discrimination laws and eventually the tax code.
An excellent example is a transgender woman (a man who wants to be a woman) who is demanding a sex change operation at a Catholic hospital in California. Previous examples include the Catholic Church forced to shut down their adoption services in Massachusetts, because they refused to place children in practicing homosexual households.
These examples point out why these "sexual orientation" provisions in anti-discrimination laws are so insidious. I recall here in Minnesota when sexual orientation was jammed through the state legislature in 1993; there were the usual assurances that all homosexual men and women wanted was to be left alone. Since then and most obviously with the push for homosexual marriage, the rally cry is for societal and governmental endorsement not just tolerance of homosexuality.
The biggest threat and obstacle to ultimate goals of the homosexual activists will always be the church which embraces the moral vision that sexual behavior outside of marriage is always wrong and that of course includes homosexual behavior.
Well, the church has flourished and prevailed under far, far worse persecution and attacks than these and no doubt will again. But it's a sad commentary on the moral drift in our nation. A drift which is harmful for all concerned.