Here is how I see it:
Amendment 1
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof;
Congress has NEVER tried to establish an official religion. However, what we see now are many attempts by the left to make Congress "prohibit the free exercise" of religion. And it is this second phrase which has been the most ignored. As I said, the phrase "separation of church and state" exists NOWHERE in our Constitution (though the Soviets did have it).
Amendment 10
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
The Constitution is the framework for the FEDERAL government and Congress is a FEDERAL body. Congress is banned from establishing a state religion; however, any state clearly can unless the individual state's constitution prohibits it. Nearly all of the cases we see in court are against state or local governments, it should never even be a federal issue.
And what does that say about society at the time? I have a hard time imagining any atheist or other non-Christian saying "in the year of our Lord". AD I can see, because A and D are just two letters of the alphabet. But I can't imagine anyone uttering that full phrase without understanding the import of it. Maybe it's just me.