Two things are obvious from reading the gospels. The first is that Jesus proclaimed the inbreaking, in his person, of the Kingdom of God/Heaven as an earthly reality. This means that the transformation of the world includes the transformation of individuals and thus their politics. The second is that this Kingdom confronted the religious and political realities of his day in the name of justice. This amounted to a social revolution that sought justice for the economically, socially, religiously and politically oppressed, ie it was a revolution from below.
The narrative arc of the gospels tells us that he was crucified because he was a threat to those who wielded power, be they the religious or civil authorities. The gospels are political. Any attempt to describe them as "spiritual" in that they do not address the real plight of men and women in their situations is ludicrous. When we read the teachings of Jesus, we are bound to come to the conclusion that he was more than a bit of a lefty.
The point of contact between politics and Christ is Christian anthropology; the view of humanity. It is the recognition that to be truly human, to become what we essentially are, we will be social and communal beings. We learn that our lives will not be found in self-interested striving or in the endless pursuit of the chimera of happiness, but in the person next to us, the neighbour. Indeed, we are told that if we would have our lives, we will lose them but if we lose our lives, we will have them. The relationship with the neighbour must first to be based on justice, what is fair, but it goes beyond that, it goes to actually loving the enemy and blessing them when they curse us.
The Kingdom of God/Heaven is a parable about a social destination, it is not an identification. Its description is poetic rather than programmatic. Unlike the utopias we map out, it is more a provocation, an irritant, or the leaven that transforms the whole lump. It transcends all ideologies and can be owned by none.
The Kingdom is a work in progress. We see fragments of it, and it glimmers on the horizon. Its characteristics are justice, peace and inclusion. There is no set pathway to it. Indeed, it may be progressed under socialism or capitalism. The factory owner may be involved in its flourishing as may the collective. What we do know is that it is brought about by men and women who have been decentred by the gospel so that they see the meaning of their own lives in others. On one side, it will be a critique of capitalism that answers only to the profit of the shareholders, on the other, a critique of socialism that places the state before the people.
There are dangers in plotting a course to the Kingdom. There have been many attempts at establishing the rule of God on earth (Theocracy), all of which have failed. The problem is that Christians think that they know the difference between good and evil. This means that attempts to establish the rule of God on earth have been based on morality. While the moral life is certainly important, morality does not capture the essence of the Kingdom, which is resurrection, the coming to life out of death of individuals, communities and the natural world. When we reduce the Kingdom to the "common good" or a lawful and ordered society, it becomes our own project and it is bound to fail. Marxism is the big example of our time.
Again, the Kingdom is a parable and not a plan. The most potent act of the Church is the Mass/Eucharist in which the table is set for all humankind and we partake of spiritual food. The Mass is the sign in our time and place of the Kingdom. While the sermon is the Kingdom argued for, declared, explained and illustrated, the Mass is the Kingdom enacted. Thus, the act that points towards the Kingdom occurs not in parliaments and courts but around the Eucharistic table. It is celebrated as a reality that is brought to us by God.
The Kingdom cannot be owned, particularly by a political party, that is why to use a name such as "Christian Democrat" is a mistake. The name "Christian" escapes definition as part of something else, like "Christian school" or "Australian Christian Lobby". Indeed, the use of the title should be a warning that something is not right, that there has been an attempt to confine the infinite within the finite, to identify something as Christian and therefore stand in the right. This is dangerous religious behaviour in the worst sense and can only lead to the establishment of similar powers to those that contributed to the murder of Christ. The same can be said about any attempt at a Christian ethics or values. The gospel is always more outrageous than our confining morality.
The Kingdom is quite different from both the ideologies of the left and the right that limit thought so that it only runs along approved pathways. Thus, the Soviet Union was tied to Marxist/Leninist theory that blinded the party to the evils of its programs. Thus, capitalism, with its insistence on individual striving and choice cannot see the real people who have never had a chance to strive or make a choice about their lives.
If the gospel produces the social person, that person cannot walk on the other side when he sees someone in trouble. We cannot, as a nation that is imbedded in the social, neglect the poor by blaming them for their poverty. This is not shallow moralism about being nice to others but the expression of an engrained characteristic in the human soul. We are not embodied selfish genes, but social actors bent on the welfare of the person we meet. The parable of the Kingdom coincides with deep humanism in that it traces out that which is appropriate to human freedom and flourishing. It is our natural state, the desire of nations.
The Christian revolution, that points to the Kingdom, cannot be fought on the basis of class or wealth. To wage a class war would simply replicate the failure of previous revolutions. However, the Kingdom will be critical of social and economic inequality produced by an unjust economic system that manages to keep the poor and the rich in their respective places. This is a critique of capitalism in our time. The Kingdom seeks community rather than the dog eat dog ethics of the market.
The Christian revolution cannot be based on a secular understanding of progress even under the guise of making the world a better place or acting for the common good. We have seen these attempts before and how they become tyrannical as various utopias come and go. So often good intentions lead to bad outcomes. This occurs because "making the world a better place" so easily becomes ideology and eventually a form of religious narrowing of options. The new puritanism, in which public figures are destroyed without recourse to law is an example.