The various writings of the New Testament have an interesting approach to the first century culture and to culture and politics in general.
At a certain level, there is a deliberate lack of engagement with local culture and politics. Jesus does not attempt to overthrow the Roman government and when challenged regarding Roman taxes, has a famous response about giving to God the things of God and giving to Caesar the things of Caesar. In a similar way, Paul makes no attempt to overthrow the first century institution of slavery, but does pressure Philemon to free his runaway slave, Onesimus.
On a different level, there is a direct and confrontational approach to culture and politics. Jesus forgives tax collectors and prostitutes and confronts religious hypocrites and the control of Jewish leaders. In personal interactions, he tells an adulterous woman to "go and sin no more" and gets a tax collector to promise to repay everything he has stolen. In a similar way, Paul confronts the jealousy and gluttony of the church in Corinth and insists that they are to be a model of the kingdom of God.
So how are Christians to engage in their culture and community? I want to lay out some principles from the New Testament readings.
1. It begins with the heart. There is such a human desire to change other people. But one cannot engage as a Christian in the community unless one begins with their own life, recognizing their own selfishness, self-deception, jealousy, ego. The world changed in the first century because people changed, because individuals committed to joining the Kingdom of God, not because they tried to enforce "religious" actions on others. If I want to be an agent of change, then the first person I should hope to see changed is me.
2. It relies on the Holy Spirit and God's power and sovereignty. God changes people; my life is changed as I allow the Holy Spirit to work. Paul repeatedly tells believers to pray and "not be anxious." Change comes not through a legalistic set of resolutions but through genuine concern and love for others, seeing others through God's eyes.
3. The church has authority only over the church! In I Corinthians 5, Paul confronts a very human desire to tell others what to do. There, in verses 12-13, he asks, "What business is it of mine to judge those outside the Church?" If one says, "I am a believer and want to be part of your believing community," then it is appropriate to say, "Our community of believers has both rights and responsibilities." It is only within the community of believers that Paul lays out expectations for truth, love, honesty and generally healthy community behavior.
4. The most common threat to the body of Christ seems to come from religious authorities! Throughout the New Testament the direct conflict to the young church comes first from Jewish religious leaders and later, occasionally, from pagan religious leaders (such as the followers of Diana in Ephesus, see Acts 19:23-41.) It might be pointed out that religious leaders have often worked out a way to profit financially from their religion and so find true religion a threat.
In the United States, Christianity has suffered greatly at the hands of religious leaders who claimed to represent Christian beliefs and then used those beliefs for political gain. I recall Richard Nixon, in 1972, getting Billy Graham to endorse him; Nixon also presented himself to the Explo '72 crowd as a Christian president who fully supported the evangelistic goals of Campus Crusade. (I was there.)
I could list numerous examples that followed. Routinely religious leaders (see item 4!) have used Christianity as a way to gain power, bully those who don't believe (item 3), pressure people to be anxious and frightened (#2), while routinely living personal lives of greed, jealousy, lust and abuse (#1.)
The only comment I might make about current US politics is already said in this link. However, let me give a more general example of how not to engage in culture change.
A US television network tells people there is "a war on Christmas." It encourages its viewers to get angry and fight against this war. (See items #2 and #3.) As it encourages Christians to speak up to "preserve Christmas", the network's ratings go up and certain "Christian" leaders gain popularity (#4.) But if you are a believer and follower of Jesus, why engage in this? Relax! God is ultimately in control. If you want to "preserve Christmas", make it a time of joy and kindness. Remember the Messiah born in the Jewish city of David, who died for all humankind. Let nonbelievers celebrate the holiday (or not) as they wish. And be leery of people with financial incentives (ad revenue) who attempt to get you to abandon compassion for conflict.
