To find out how we accomplish this we must first look at what each of them are and why they exist.
What is the Church?
The Church is a place for which children may Grow and Learn about Existence, share common knowledge and understandings and open there hearts and minds to the Love of Life with the intent of educating Sanctity of All Life as the Will of God.
What is the Government?
The Government is another construct designed to enable morality, logic and reason as a established system to assist the individuals of that specific nation maintain order, peace, and sanctuary to the citizens for which it holds.
How are these two designed to interact?
When the church becomes over bearing on any one subject, lets say when the church attempts to FORCE Sanctity or FORCE Purity and then uses Damnation or any other means of manipulation it becomes the governments position to enforce Human Rights and Laws that give the individual the ability to retain Free Will as is Gods Will as well for the church and God do not Command. When the Government condones and preforms an insensitive act against Life and Love under Heaven as is Gods Will it is the Purity and Sanctity of the church that will stand up and Voice itself against such injustice under Heaven.
How can we Unite Church and Government?
"Education" on the design of each construct and the end goal of Humanity is how you unite both. A literal walk through of what we are to become, how we become it, each church and government will identify the Sanctity of All Life missing from there Society and Social structures and with Science now backing up Gods Will the Church and Government now know exactly what this means. The Church can no longer hide information. The Governments and the Church now know what God is asking and why. God even told you How.
The end result will be Harmony as the Governments and Church's of the world assist us in guiding society and social structures towards the same goal, where science and technology permit our existence to transition away from immorality all together as step by step endeavor to refine ourselves and the Humanity for which we exist.
Each government and church was created to house and protect the lifeforms and individuals. This is a fact you may not want to accept but, God created every nation on this rock, every religious practice was guided literally by the same Energy. All religions of the world are missing something, Now they are not. From this you will understand your duty to God and Country quite literally...
Stage 2-3-4 will also help...
Read the Grail for yourself...