Yet the ACLU has been able to acheive its goals without public support.
You claim we would only go back to the 1960's. Why should they stop there? Why not to 1700?
One route to wider public acceptance for an intrusive role of religion in government is to obtain control of public schools. The American people, right now, would not accept the stoning of disobedient children or the execution of homosexuals and apostates. But they did once, and there's no reason to believe that their attitudes, having been changed once, could not be changed again.
The ACLU uses the courts to override the will of the people. It also has the media in its pocket.
One route to wider public acceptance for an intrusive role of religion in government is to obtain control of public schools. The American people, right now, would not accept the stoning of disobedient children or the execution of homosexuals and apostates. But they did once, and there's no reason to believe that their attitudes, having been changed once, could not be changed again.
But these people are nowhere close to obtaining control of public schools. And furthermore, history shows that religious (or other) extremism doesn't take hold of a country in normal times, but rather in abnormal, crisis-ridden times. And if we should be faced with a crisis of the type that historically has given rise to it, then it'll happen whether it's sanctified by the establishment or not (in fact not being sanctified can accelerate it, as in the case of the American Puritanism that you referred to in your post). It's far too distant and theoretical a concern for it to be taken seriously as a matter of public policy, especially when the trend is so manifestly in the opposite direction.
And it's also comparatively easy to use public schools and popular media to entice people, and especially children, to socialism, multiculturalism, and other "feel-good" stuff. A lot harder to entice them to Draconian religious impositions. Accomplishing that requires a whole different set of prerequisites that just don't exist in the U.S. today.
1709? By then America was no longer hanging "witches"
Uh, no, they didn't. Even Hester Prynne wasn't stoned to death.
Two can play this game. You want to attack religious believers? Well then, the Communists are your allies. Don't like being tarred with that brush? Then you should take a bit more care in your distinctions.