The New Testament has no mandate for the construction of a Christian government short of the return of Jesus Christ in person, so any attempt to construct one is by definition extrabiblical. You’d certainly get a grand fight against this concept by most mainline fundies, including the Southern Baptists.
What most fundies would like to see is evangelization success at the personal level. When the PEOPLE who carry out government are Christian, then Christian values will prevail and it will be, in fact, more tolerant towards other faith systems than a government of agnostics and atheists would be.