The church's role in government:
Matthew 28:18-20 KJV
And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth. [19] Go ye therefore, and
teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: [20]
Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen.
Mark 16:15 KJV
And he said unto them, Go ye into all the world, and preach the gospel to every creature.
"Every creature" includes everybody in government, from the king or President down to the dogcatcher. The church is commissioned by Christ to be the teacher to all nations and everybody in those nations, including their governors and rulers. The goal is to evangelize not just the random people on the street or the random visitors to the church house, but every nation and everybody in those nations, from top to bottom and side to side. Our job is to be the hands and feet of God in converting the entire world to Christ.