&gt; There are many nation-states with 1 or N state-recognized religions, as you point out<p>No, I&#x27;m taking about <i>state religions</i>, not merely state-<i>recognized</i> religions. These are different. There&#x27;s only one established religion in the UK, the Church of England, but it is absolutely possible to have your marriage officiated by a non-Anglican or even non-Christian minister. It would be completely wrong to claim that the Roman Catholic Church has been an established church in the UK ever since the Marriage Act 1836 allowed its priests to officiate marriages, or that the CoE is now disestablished because the CoE doesn&#x27;t permit gay marriage but gay couples can get legally married in other churches. Finland is another example; there are exactly two state churches but dozens of &quot;registered&quot; churches where one may marry.<p>There is, of course, an extension to be read into that part of the Constitution about not favoring a church in governance; it&#x27;s sort of the same way the Constitution has an unwritten right to privacy. But you can only read it in so far. It is not a constitutional prohibition on the recognition of churches, just on the establishment of churches. That word had a very specific meaning separate from &quot;recognition&quot; in 1789; it is a testament to the success of that amendment that we in the US have forgotten what it means.<p>It is worth noting that while everyone who wrote that amendment was still around and deeply involved, Congress wrote this resolution (<a href="http:&#x2F;&#x2F;memory.loc.gov&#x2F;ll&#x2F;llac&#x2F;001&#x2F;0000&#x2F;00160025.gif" rel="nofollow">http:&#x2F;&#x2F;memory.loc.gov&#x2F;ll&#x2F;llac&#x2F;001&#x2F;0000&#x2F;00160025.gif</a>):<p>&quot;Resolved, that after the oath shall have been administered to the President, he, attended by the Vice President, and members of the Senate, and House of Representatives, proceed to St. Paul&#x27;s Chapel, to hear divine service, to be performed by the Chaplain of Congress already appointed.&quot;<p>And nobody thought that respected an establishment of religion.<p>(This is not to say, btw, that I personally agree with all of our current policies. I&#x27;d very much like to see us further disentangle legal marriage from religious marriage. I just don&#x27;t think we have anything close to a Constitutional obligation to do so, and we should do so because we the people want to. Being fortunate enough not to have an established church, we also have no Constitutional obligation to stick with the present system, either.)