Romans 13:1-2 says: Let every soul be subject unto the higher powers. For there is no power but of God: the powers that be are ordained of God. For he is the minister of God to thee for good. But if thou do that which is evil, be afraid; for he beareth not the sword in vain: for he is the minister of God, a revenger to execute wrath upon him that doeth evil (Romans 1:4).
Any authority given by God to exercise over others has boundaries set by God. God is the ultimate authority because He is "far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come" (Ephesians 1:21). Many Christians in the modern church fail to take this for what it means, that is, God being Sovereign above absolutely all things, and assume that God allows humans to govern as we choose, as long as it is just. This is a deceptive statement because while God does not prescribe any system, He does however, ordain any government to be just and righteous according to His Law, regardless of whether they realise it or not. The philosophy underlying a political system determines whether a system of government will be just and righteous per se and each system is defined according its philosophy.