Is the church a polis herself?  Or a replacement for the pagan cults at the heart of the ancient polis?

There might be another way to say it.  Erik Peterson ( Das Buch von den Engeln , 1935) points to the NT language about a heavenly Jerusalem of which Christians are citizens.  He compares the church to the pagan cults this way: “One might perhaps say, that as the profane Ekklesia of antiquity was an institution of the polis, so the Christian Ekklesia is an institution of the heavenly city, of the heavenly Jerusalem.”

That’s sharp: On this view, the church is never absorbed into earthly political order, never reduced to a national cult, even if the nation is thoroughly Christian.  The political order to which the church belongs is the eschatological political order of the heavenly city.  At the same time, this view seems to avoid some of the separationist tendencies that sometimes infect church-as-polis theories.   The church isn’t defined over-against the earthly city, but as the sacrament and “cult” of the city that is to come.