Political theologians from an Anabaptist tradition describe how Christian community is to function as a counter or contrasting polis to the nation state. That is, the Christian community is to embody and instantiate a politics, a way of sharing life together that displays an economy of material, relational, and spiritual commitment and care.
Such communities are what we'd call intentional communities, groups of Christians who agree to share a common life together, materially and communally. Examples include the Amish, the Bruderhof, the Catholic Workers, the New Monastics, and the entire monastic tradition. The goal of these communities isn't to change the nation state or overthrow capitalism. The goal is to embody and enjoy a new world--a different politics, economy, and community--in the midst of the old.
And beyond Christianity, we see all sorts of other intentional communities, nomadic lifeways, communes, and anarchist experiments where people are trying to escape the tyranny of the state and market.
It must be said, however, that intentional Christian communities are rare. It is common in Christian discourse about the church to describe the church as a counter-polis to the world. Few churches, however, actually embody a new and different politics, where the material fortunes of its members are tightly knit together in a shared fabric of interdependency and mutuality. This is not to say churches don't share material goods with each other or the world. They do, but they do so as a form of leavening presence through charitable giving, tithing, and benevolence ministries, extending help to those within the church or in the world who find themselves in need. But charity and benevolence does not instantiate the distinct and contrasting politics as one would find in intentional Christian communities.
To be sure, as we noted in the contrast between Christian realism and revolution, we can recognize a continuum here. There are gradations between leavening presence and intentional community. Christian communities and churches can express a range of material commitments in their common life, and smaller groups within a church can share life together in very intentional ways. And beyond material sharing, there are a host of ways of sharing cultural life together, as we see in the homeschooling movement and BenOp expressions.