When the state actively persecutes the followers of Jesus Christ, it is easy for those followers to experience this conflict and even find comfort in it. And yet, the conflict from the perspective of the church taking the long view and not focusing on any one theorist within the history of the church or Christianity is that the conflict is due to factors that aren't due to God's intentions for the world. The church call's the polis, the State, the Nation-State to its truest and most just reality. The conflict remains thought because the polis, the state, the Nation-State, the Empire retains its fallen inclination towards self-preservation and self-justification, which it shares with all humanity. The conflict arises because the Church is to be the polis in which the citizens shed this egocentric self, and put on Christ, become a new creation, and new creature. It is the polis that announces that this world, all current human systems are of an old order that must and will and has already begun to pass away.
Christians as believers in redemption, salvation and God's grace and transforming love, believe and hope in the transformation of all reality, including the polis, thus there is in this hope always the temptation to see more transformation in a polis or in the systems of the world than there is in actuality. Very rarely does the church see this in their own time thought it can become glaringly apparent to those who live some distance in time and space from other systems. Many contemporary Christians are aghast that any Christians actually thought Constantine's conversion was real or even beneficial the the church. Yet those same Christians see nothing contradictory to tying themselves and their faith, to democracy, or communism, or America, or even more astoundingly a political party or a particular president (at least two in recent memory of opposite parties).
However, whether in Byzantium, or Medieval Europe, or America there have been voices that call us to allegiance to Christ only even when we the church believe we have the power and influence to affect change and reform in the systems of this world. Taking the long view and whole witness of revelation and the history of the Church it seems that we can neither wholly demonize the State, Empire, Polis, nor ever hope prior to the consummation of all things in Christ. that we can rest in a particular vision and actuality of any particular human polis. In fact we by virtue of our baptism are prohibited from so resting. We are always to be ambassadors of the world to come, of Christ, who was crucified by the systems of this world, and it alway already includes what ever system humans have created for themselves, including our current system of democratic Nation-States. We pray for leaders, authorities, nations and governments, not because the church wishes to endorse them but because they need and we need our prayers for them, for without them human systems descend into self-interest and self justification, and justice is defined by what those in power deem to be justice. This is true today as much for progressives and conservatives, or whatever definitions and labels one puts on human attempts to organize and control each other.
Back to an earlier point: Nation-States emerge out of a conflict with the church (one that perhaps the church did not fight well, and in so doing may have compromised its witness even as it tried to witness to its proclamation of the coming of God's reign in the world), in such a way that the state came to see itself in terms of the church. It in various forms and with various apologies and philosophies and economic theories, has attempted to claim that it can change and transform the human soul. That it should be allowed to legislate a better and Utopian world. that it should coerce people whether by force of arms or simply executive orders, laws, and regulations into being selfless. Yet, it denies its own selfish ambition, and the power that then brings to those who either through election or force of arms hold the reigns of government. Oddly enough the church has as often as not sought to tie its fortunes to these divine imperial claims of the state, and encouraged the notion that the state can be a trans-formative force in the world. If or one am naming that claim as blasphemous and idolatrous even if it may accomplish some good in the world.
Also those above claims reduce our own personal human responsibility, it throws upon the state our call to care for our fellow human beings, in the name of efficiency of a central authority that can direct and control outcomes. Well we know how well that works don't we, and yet we keep trying it.