I really struggle over the relation of the church and the state. I respect scholars and Christian traditions in their various takes on the matter. I think there’s often good we can take out of varying viewpoints.
That said, I also think the so-called “Constantinian turn” of the church when the Roman Empire became formally Christian, was in some sense the death knell of what the church is called to be in the world: a witness to another lord, the one true Lord, and to the one good news in him. One can plausibly argue otherwise, and surely some of what they say will have plenty of truth in it. But a major problem I see today in the United States is the emphasis on the importance of the morality of the state, as if it somehow ought to be Christian in some way or another. This is the case from both the religious left and the religious right, the former emphasizing world peace and the right to do whatever, and the latter emphasizing a certain morality as in “family values.” Both have a code of ethics, but the attention is turned almost completely to the state, it seems.
Regardless, this is my take on the current sea change in the United States, of course same sex marriage, etc., all in the equation. The church needs to hold the line both on the teaching of the gospel: the good news concerning Jesus, and righteousness: God’s will in Jesus. And of course, that is to be a witness for the world, hopefully impacting the state for good. But the church must neither be influenced by the world, nor expect the world to be influenced by it. If I read the Bible right, that is. But to hear people both from liberal, progressive and conservative perspectives, you would have to think that much depends on what the state is doing, that is all that essentially seems to matter, and the church is present to applaud and support that.
It doesn’t matter one whit what the world does, what the state does, the church must kindly tow the line, holding to the teaching of our Lord, of righteousness. The church always must pray for the state, and be a witness to it of the power of Christ and the gospel. And it does need to be present for the good of all, including the state, praying for its blessing, as well as for the good of all people.
But the church must be careful not to compromise its calling to be a witness to the one good news in the one Lord and Savior, Jesus.