Congress shall make no law . . .That amendment as written had nothing to do with the right of a particular state to have an established church, or to regulate religious exercise in a way forbidden to the Federal government. Such practice by the states is not now typically blatant, but in fact there were established churches in the U.S. after the adoption of the First Amendment.
The genius of the Constitution is its design for the cooperation of states and individuals who must content themselves to "agree to disagree" on some points which are important to them. I think the Framers of the Constitution wanted to think that in principle a Turkey--if not, indeed, a Saudi Arabia--could be a member of the federal union. IOW, the "United" Nations design is a flawed reinvention of the Articles of Confederation when the need is for a global adoption of the Constitution of the United States of America.
But of course history shows that the court system is the rub. Anyone would agree to that, if they believed that the courts would do what they wanted--and would oppose that if they did not. And we ourselves cannot unambiguously recommend our own system for selecting judges--we do not even know ourselves how to design a Supreme Court and subordinate court system which could be fully trustworthy. So even U.S. conservatives who revere the Constitution cannot recommend that the SCOTUS be given global scope.
Of course the Seventeenth Amendment would have to be repealed in order to attract foreign states into the union, and that would ameliorate the court problem at least somewhat.
It's too bad that there is not another one, sating....
"Congress shall steal NO money...."
It's the Federal extortion that gets most of others to 'toe the line': "If your state don't do what we want, we'll withhold money that we've taken from YOUR citizens and give it to others who DO do what we wish."