Joseph: The Blaine amendment, which is in many state constitutions, has been upheld frequently. It is based on the “establishment” clause, on the theory than any religious institution that is publicly funded becomes established.
And would you really want to have the government having a “Secretary of Religious Affairs” deciding which Rav would work in which shul, and what their Shabbos drasha would be. At the very least, government funded yeshivos would be required to toe the line ideologically, and that would be as bad as New York’s current plan to force yeshiovos to adopt secular, un-frum curricula.