Read this and answer the question. If the question is unanswerable, say "unanswerable".

Critics of the modern concept of the "separation of church and state" argue that it is untethered to anything in the text of the constitution and is contrary to the conception of the phrase as the Founding Fathers understood it. Philip Hamburger, Columbia Law school professor and prominent critic of the modern understanding of the concept, maintains that the modern concept, which deviates from the constitutional establishment clause jurisprudence, is rooted in American anti-Catholicism and Nativism.[citation needed] Briefs before the Supreme Court, including by the U.S. government, have argued that some state constitutional amendments relating to the modern conception of separation of church and state (Blaine Amendments) were motivated by and intended to enact anti-Catholicism.

What do critics of the concept of separation of church and state argue it's tethered to?
unanswerable