The whole modern world has divided itself into Conservatives and Progressives. The business of Progressives is to go on making mistakes. The business of the Conservatives is to prevent the mistakes from being corrected.
GK Chesterton
The vast majority of Christians in America have accepted the Constantinian notion that the primary political task of the church is to rule, to be in charge. What that means at the very least is that Christians are to play a prophetic role in the political court of Washington DC. Second, it means that most Christians have accepted the modern dichotomies of left/right, liberal/conservative, Democrat/Republican.
In accepting these two "truths" the problem becomes clear. As Christians, instead of identifying ourselves as primarily kingdom citizens, we see ourselves first and foremost as Democrats or Republicans, conservatives or liberals. The Sermon on the Mount gets eclipsed by the political platforms of the DNC and the RNC. We like to say that we transcend such earthly contrived political conventions, but we can point to very little evidence to show that this is indeed the case. James Dobson is clearly a conservative Republican and Jim Wallis is obviously a liberal Democrat. The only truth they speak to power is their own Republican or Democratic truth to the power of the other party. The criticism of their own is basically absent or woefully inadequate at best. It appears that both men desire to play the role of Nathan in David's court, but they find they only have influence in that court when "David" is part of their own party; and then their prophetic denunciations are reserved only for the opposition outside the court and not those who are in power. They have very little of a prophetic nature to say to the king from their own party whom they serve. In other words, the church cannot speak truth to power because the church itself is up to its armpits in power and, therefore, has a stake in such power.
In cosying up to the principalities and powers, Christians on the left and the right have chosen the politics of power over the politics of witness; indeed, they cannot even imagine, in spite of what they say, what the politics of the Kingdom of God might look like apart from the politics of left and right.
Allan Brevere on Why the Church in America cannot Speak the Truth to Power
Democracy means simply the bludgeoning of the people by the people for the people.
Oscar Wilde