That which makes the church "radical" and forever "new" is not that the church tends to lean toward the left on most social issues, but rather that the church knows Jesus whereas the world does not. In the church's view, the political left is not noticeably more interesting than the political right; both sides tend towards solutions that act as if the world has not ended and begun in Jesus.
For example, when Christians discuss sex, it often sounds as if we are somehow "against sex". What we fail to make clear is that sexual passion (the good gifts of God's creation) is now subservient to the demanding business of maintaining a revolutionary community in a world that often uses sex as a means of momentarily anesthetizing or distracting people from the basic vacuity of their lives. When the only contemporary means of self-transcendence is orgasm, we Christians are going to have a tough time convincing people that it would be nicer if they were not promiscuous.
The cross is not a sign of the church's quiet, suffering submission to the powers-that-be, but rather the church's revolutionary participation in the victory of Christ over those powers. The cross is not a symbol for general human suffering and oppression. Rather, the cross is a sign of what happens when one takes God's account of reality more seriously than Caesar's. The cross stands as God's (and our) eternal no to the powers of death, as well as God's eternal yes to humanity, God's remarkable determination not to leave us to our own devices.
On the other hand, activist Christians who talk much about justice promote a notion of justice that envisions a society in which faith in God is rendered quite unnecessary, since everybody already believes in peace and justice even when everybody does not believe in God.
We would like a church that again asserts that God, not nations, rules the world, that the boundaries of God's kingdom transcend those of Caesar, and that the main political task of the church is the formation of people who see clearly the cost of discipleship and are willing to pay the price.
The church is not to be judged by how useful we are as a "supportive institution" and our clergy as members of a "helping profession". The church has its own reason for being, hid within its own mandate and not found in the world. We are not chartered by the Emperor.
I fear that much of the Christianity that surrounds us assumes our task is to save appearances by protecting God from Job-like anguish. But if God is the God of Jesus Christ, then God does not need our protection. What God demands is not protection, but truth.