JISHOU, HUNAN — Serendipitously, here’s a quote from President Grant, speaking before Civil War veterans a century after Adams wrote his letters.
Let us all labor to add all needful guarantees for the security of free thought, free speech, a free press, pure morals, unfettered religious sentiments, and of equal rights and privileges to all men irrespective of nationality, color or religion. Encourage free schools, and resolve that not one dollar, appropriated for their support, shall be appropriated to the support of any sectarian schools. Resolve that neither the state nor nation, nor both combined, shall support institutions of learning other than those sufficient to afford to every child growing up in the land the opportunity of a good common school education, unmixed with sectarian, pagan, or atheistical dogmas. Leave the matter of religion to the family altar, the church, and the private school, supported entirely by private contributions. Keep the church and state forever separate. With these safeguards, I believe the battles which created the Army of the Tennessee will not have been fought in vain. (Source)
The context for his remarks were sectarian battles in many cities about what religious ideas should be taught in tax-supported schools. Grant’s answer was simple: none.
In his annual address before Congress in 1875, Grant continued in the same vein.
As this will be the last annual message which I shall have the honor of transmitting to Congress before my successor is chosen, I will repeat or recapitulate the questions which I deem of vital importance which may be legislated upon and settled at this session:
First. That the States shall be required to afford the opportunity of a good common-school education to every child within their limits.
Second. No sectarian tenets shall ever be taught in any school supported in whole or in part by the State, nation, or by the proceeds of any tax levied upon any community. Make education compulsory so far as to deprive all persons who can not read and write from becoming voters after the year 1890, disfranchising none, however, on grounds of illiteracy who may be voters at the time this amendment takes effect.
Third. Declare church and state forever separate and distinct, but each free within their proper spheres; and that all church property shall bear its own proportion of taxation.
— Annual Message to the Senate and House of Representatives, December 7, 1875
Funny how some of these core ideas of American government have been forgotten these last few decades.