In his classic work, Christianity and Liberalism, J. Gresham Machen shows that liberalism is not Christianity. It is another religion. Because it is another religion, it fosters a different political world and life view. The liberal in religion is likely to be a liberal in politics. Since he doesn’t believe in the infallibility of the Bible, the liberal finds infallibility in man. So he ends up with the state as infallible. Just as the Christian appeals to God’s Word as his final authority, the liberal appeals to the state for the authoritative ruling.
Thoburn, R.L. (1984). The Christian and Politics. 2nd edition. Thoburn Press, Tyler, pp. 7-8