Too many people armed only with scriptures written thousands of years ago claim to understand God's will and know "exactly" how we should behave socially and politically.
When the last books of the New Testament were written, slavery was acceptable and monarchy was the preferred form of government.
The most important lessons from the bible are, for the most part, not literally applicable to us. To better understand, we need to cut through the history, discriminate between what was present and relevant then and what is present and relevant now. We must read the subtext, and therein lies the difficulty.
For instance, many socialists claim that Jesus, with his message of charity for the weak and needy, would have advocated programs such as social security, medicaid, and medicare. Isn't it Christian to help the elderly, the poor, and the sick?
But social security, medicaid, and medicare all rely upon the violent, coercive powers of government to redistribute wealth involuntarily from the productive to the non-productive. Does love of one's neighbor come from the barrel of a gun?
Others, and I count myself among them, consider Jesus' proclamations to be calls to individual action. I should help the elderly, the sick, those weaker than I am.
According to the socialist model, my property is forcibly taken from me and (lacking major corruption), delivered to those in need. The first caveat, of course, is that socialism breeds corruption and inefficiency. The formula for helping people in this way ends up hurting more. The second caveat is that a man who pays his taxes is not charitable. He does so in order to avoid being harmed. Jesus did not say, "Blessed are the shirkers and those who cower before might." There's simply no charity in the socialist system.
According to our alternate model, men can demonstrate their devotion to Jesus' teachings by acting according to their free will.
Should the old version of the story be true, when we die and meet St. Peter at the Pearly Gates, which will be the more valid petition: "I paid my taxes," or "I gave of my own free will"?
So the trick to Christian theology isn't to say "This and this happened and in ancient Judea would have resulted in that and that, therefore the same should be true for us."
The trick to Christian theology is to strike at the meaning of Jesus' teachings, God's will itself, if you're a believer.
If you're not a believer, then you've already discounted this post. Alas.