The advocate of mere Christendom, in which category I place myself, must at some point address the question of whether or not we should have an established church. And, if so, which one? We already asked the Holy Ghost Lightning Tabernacle, but they declined.
There are layers to this, making it a fun activity, like a birthday cake. There are constitutional issues, wisdom issues, historical issues, and scriptural issues, at least, and so let us treat them in that order.
When the Constitution of the United States was adopted, the First Amendment addressed the issue of an established church at the federal level, but this did not address the Christendom question. It has been made to address it by means of revisionist history, but originally it had nothing whatever to do with it. The Constitution forbade a Church of the United States on federal grounds, not secular grounds. The document was dated in the year of our Lord 1789, and when it was adopted 9 out of the 13 states had established churches on the state level. There was no sense that the non-establishment clause was in any sense violated by those states having official state religions.
Now this does not make establishment at the state level a good idea. It simply makes it a constitutional option. Patrick Henry, who grew up in Presbyterian and Anglican circles, had been appalled by the flogging of a Baptist preacher under the laws of Virginia, as would I have been. That kind of thing should repulse us all.
If various states have their state birds and state flowers, there is no problem if the national government adopts the bald eagle, and whatever flower it was they adopted. But if the state establishment is Congregational in Connecticut and Episcopalian at the national level, you are just asking for trouble. Since the Founders weren’t asking for trouble, and were creating a federal government (and not a national government), they removed from Congress the authority to create a national church. And good for them.
After the War Between the States, the Fourteenth Amendment was adopted, and sometime later, court decisions retroactively applied the restrictions of the earlier amendments to the states — with the central government as the arbiter. This was a reversal of the form of government established by the Founders (as a glance at the Tenth Amendment should reveal), where the states jealously guarded what the central government could and could not do.
So, then, if we are going by original intent, there is nothing unconstitutional about (say) South Dakota establishing the Lutheran Church as their official denomination. Would that be a good idea? In the abstract, I don’t think so, but it would be preferable to what we have now.
What are the wisdom issues? A strong argument can be made that establishment (official recognition and tax support for the churches) is the spiritual kiss of death for those churches. As a general rule, we do not look for spiritual vibrancy among all the state’s kept clerics. This is kind of obvious, and in fact the obviousness of it has been used by many to argue for the (completely unrelated) point that the civil government does not need to conduct its business in the light of Christ’s lordship. But tax support for churches and recognition that Jesus outranks the highest human authority are distinct questions. Thus it is possible for someone (myself, for instance) to argue against establishment and in favor of our forms of government being explicitly Christian. I would want a federal republican system among civil entities, all of which are explicitly and formally Christian, and some of which may have formal church establishments. Speaking postmillennially, I would want those establishments to gradually be set aside, but they aren’t the end of the world either.
Historically, things get even more interesting. There are three basic options when it comes to church/state relations. You can have the church in charge of the state, as it was with the medieval settlement, you can have the state in charge of the church, as in Erastianism, and you can have the church and state occupying their respective spheres of authority — with each sphere established directly by God, and neither one having to answer to the other for its basic marching orders. During the Reformation, you had varying degrees of balance between the second and third options. There were certainly elements of Erastianism (the Westminster Assembly was convened by Parliament, for example, and answered to Parliament), and the Reformers expected the civil magistrate to suppress blasphemies, and so on. At the same time, there were battles in which, for example, Calvin resisted the right of the city council to tell him that he couldn’t excommunicate the Libertines. What it boiled down to was that the Reformers held that the civil magistrate had some authority in matters circa sacra, surrounding sacred things, but no authority in sacris, in sacred things. Easier said than done, but they all agreed that there was a boundary there that needed to be patrolled.
The American form of the Westminster Confession redrew that boundary, taking away some of the “circa sacra” responsibilities of the state, but their wording is consistent with, and requires, a robust Christendom. It does not require establishment, but it does require that the state recognize and protect “the church of our common Lord.”
“Civil magistrates may not assume to themselves the administration of the Word and sacraments; or the power of the keys of the kingdom of heaven; or, in the least, interfere in matters of faith. Yet, as nursing fathers, it is the duty of civil magistrates to protect the church of our common Lord, without giving the preference to any denomination of Christians above the rest, in such a manner that all ecclesiastical persons whatever shall enjoy the full, free, and unquestioned liberty of discharging every part of their sacred functions, without violence or danger. And, as Jesus Christ hath appointed a regular government and discipline in his church, no law of any commonwealth should interfere with, let, or hinder, the due exercise thereof, among the voluntary members of any denomination of Christians, according to their own profession and belief. It is the duty of civil magistrates to protect the person and good name of all their people, in such an effectual manner as that no person be suffered, either upon pretense of religion or of infidelity, to offer any indignity, violence, abuse, or injury to any other person whatsoever: and to take order, that all religious and ecclesiastical assemblies be held without molestation or disturbance” (WCF 23.3).
The fact that the American revisers urged us to see that Baptists, Presbyterians, Congregationalists, and Episcopalians all served a common Lord, and were entitled to civil protections in that capacity, is quite striking. But the fact that many of their heirs and assigns have thrown this into an ecclesiastical blender, and argue that this means the civil government must be blind to the differences between Buddhists, Muslims, Jews, Christians, atheists, and Melanesian frog worshippers tells us something equally striking, but not quite so edifying.
The scriptural point is this. The magistrate has a reponsibility to recognize that Jesus rose from the dead, and that He is seated at the right hand of God the Father, Almighty, Maker of heaven and earth. This is a scriptural requirement because the Bible says that every tongue must confess this. He has a responsibility to govern the nation with that truth in his mind and heart, and to consult with the church when he has questions about what it all means. He should also have the authority to tell the church to pipe down when clerics who don’t understand economics wax indignant about coffee bean plantations, as they like to do sometimes. He should propose an amendment to the Constitution that consists of the text of the Apostles’ Creed. He should not put any particular denomination on the dole. If we don’t like welfare queens, we should not want to encourage bishop queens. We have enough of those already.
There are three institutions among men that were created directly by God. These three institutions do not depend for their existence or authority on the good pleasure of either of the other two. These three spheres each stand alone before God, and so they are called by God to learn how to stand together, in harmony, under the common lordship of Christ. These three governments are family government (Gen. 2:22-25), civil government (Rom. 13:1), and church government (Eph. 4:10-12). We have the authority under Christ to create other lesser spheres, but these are the three from God. Our task is to balance them rightly, not add to them, or subtract from them.