As an evangelical Christian but a strong critic of President Trump, I have a hard time seeing the unwavering support he has from the "Court Evangelicals", and, subsequently, from many evangelicals out in the pews and wider society. It makes me crazy! How do they justify it?
Two Kingdoms theology, that's how. This article was what got my education started (well, after my interest was piqued by Dr. Fea's excellent blog). The Court Evangelicals, particularly Dr. Jeffress, are deploying Two Kingdoms theology which says that the earthly kingdom of the state and the heavenly kingdom of God are two separate realms to which Christians relate differently.
The kingdom of God is the spiritual kingdom that governs the behavior of Christians. We are to follow Jesus, take up our cross daily, and love one another.
The kingdom of the state, though, is a temporal kingdom ordained by God to keep order in society. The state may or may not be Christian. We are enjoined in Romans 13 (and elsewhere) to submit to governing authorities without reference to whether or not those authorities are Christian.
Two Kingdom theology can be a good explanatory model for how Christians should relate to the rest of the world. Here is a useful article by Michael Horton explaining Two Kingdom theology, going back to Augustine and Luther. As Christians, we are members of both kingdoms. And we can expect to do good in both kingdoms.
The Two Kingdom theology as practiced by many evangelicals today is problematic because it is being used to justify their support of an immoral president (originally, candidate) and, increasingly, problematic Republican Party. Back in the early 1990s, when Bill Clinton was running for the presidency, evangelicals were appalled at his personal life. Clinton was known for his sexual promiscuity. Evangelical leaders at the time pointed out that a man who couldn't be trusted by his wife couldn't be trusted by the country. They also were concerned that the highest office in the land should be held by a person of high moral character, which they did not believe Clinton was.
Fast forward 20 something years, and evangelical leaders are happy to support Donald Trump, a man also of low moral character. Yet, now, evangelicals have come up with many ways to excuse his grabbing women's genitals, having had multiple affairs, and paying a porn star to keep her from talking about their affair. (I will grant you that some evangelicals voted for Trump in order to not vote for his opponent and at least some of them are having some buyer's remorse.)
Our evangelical leaders are telling us now that character doesn't matter in our president because he is the leader of the state and our responsibility as Christians is only to be part of the kingdom of God.
Not only that, but when the administration makes policy decisions that seem to be contrary to Christian values, such as harsh immigration stances or actions that hurt the poor or disenfranchised, our evangelical leaders again use the Two Kingdoms theology to tell us that the state doesn't follow need to God's law, only individuals need to.
Yet, here's a problem. In a representative democracy, the "state" or government is the people. We elected the president and the Congress. The "state" isn't some arbitrary "thing" out there making decisions without human input. The state is us. And we, as Christians, live in both the Kingdom of God and the Kingdom of the world.
As those who dwell in both kingdoms, we must have our faith inform not just our actions as individuals, but our actions as members of the state (i.e. in elections or as elected officials even in such positions as humble as school board or town council). I don't buy it when Dr. Jeffress says that the President "shouldn't embody Jesus' teachings on the Sermon on the Mount."
The President, if he is a Christian as he claims, should be following Jesus and putting into place his Christian values whether as a representative of the kingdom of God or the kingdom of the world (state). Even if our elected representatives are not Christians, they should be bringing their highest moral sensibility to everything that they do. As Christians, that moral sensibility is based on their faith in Jesus. The government may not be Christian, but it's actions must be based on the values of the people who make it up.
Two Kingdom theology doesn't mean that we give up our Christian identity when we act in the kingdom of the world. All of us, from the President on down, are part of both the kingdom of God and the kingdom of this world. We are obligated to bring our highest moral and ethical actions to bear on everything that we do. Two Kingdom theology doesn't give President Trump a pass on his actions. In fact, it places on him more responsibility. Just as it does on all of us.