The radical separation of church and state proposed by some folks that I would designate as "R2K" rather than "2K," is contrary to the Westminster Standards. Practically everyone knows that such positions are contrary to the original Westminster Standards (and, of course, to the Standards as modified by the RPCNA testimony), but these positions are also contrary to the standards as amended by the Americans.
Westminster Confession of Faith (American Revisions)
2. It is lawful for Christians to accept and execute the office of a magistrate, when called thereunto: in the managing whereof, as they ought especially to maintain piety, justice, and peace, according to the wholesome laws of each commonwealth; so, for that end, they may lawfully, now under the new testament, wage war, upon just and necessary occasion.
3. 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.
4. Synods and councils are to handle, or conclude nothing, but that which is ecclesiastical: and are not to intermeddle with civil affairs which concern the commonwealth, unless by way of humble petition in cases extraordinary; or, by way of advice, for satisfaction of conscience, if they be thereunto required by the civil magistrate.
Westminster Larger Catechism
Q. 191. What do we pray for in the second petition?
A. In the second petition (which is, Thy kingdom come), acknowledging ourselves and all mankind to be by nature under the dominion of sin and Satan, we pray, that the kingdom of sin and Satan may be destroyed, the gospel propagated throughout the world, the Jews called, the fullness of the Gentiles brought in; the church furnished with all gospel officers and ordinances, purged from corruption, countenanced and maintained by the civil magistrate; that the ordinances of Christ may be purely dispensed, and made effectual to the converting of those that are yet in their sins, and the confirming, comforting, and building up of those that are already converted: that Christ would rule in our hearts here, and hasten the time of his second coming, and our reigning with him forever: and that he would be pleased so to exercise the kingdom of his power in all the world, as may best conduce to these ends.
Q. 108. What are the duties required in the second commandment?
A. The duties required in the second commandment are, the receiving, observing, and keeping pure and entire, all such religious worship and ordinances as God hath instituted in his word; particularly prayer and thanksgiving in the name of Christ; the reading, preaching, and hearing of the word; the administration and receiving of the sacraments; church government and discipline; the ministry and maintenance thereof; religious fasting; swearing by the name of God, and vowing unto him: as also the disapproving, detesting, opposing, all false worship; and, according to each one's place and calling, removing it, and all monuments of idolatry.
Q. 118. Why is the charge of keeping the sabbath more specially directed to governors of families, and other superiors?
A. The charge of keeping the sabbath is more specially directed to governors of families, and other superiors, because they are bound not only to keep it themselves, but to see that it be observed by all those that are under their charge; and because they are prone ofttimes to hinder them by employments of their own.
Q. 124. Who are meant by father and mother in the fifth commandment?
A. By father and mother, in the fifth commandment, are meant, not only natural parents, but all superiors in age and gifts; and especially such as, by God's ordinance, are over us in place of authority, whether in family, church, or commonwealth.
Q. 129. What is required of superiors towards their inferiors?
A. It is required of superiors, according to that power they receive from God, and that relation wherein they stand, to love, pray for, and bless their inferiors; to instruct, counsel, and admonish them; countenancing, commending, and rewarding such as do well; and discountenancing, reproving, and chastising such as do ill; protecting, and providing for them all things necessary for soul and body: and by grave, wise, holy, and exemplary carriage, to procure glory to God, honor to themselves, and so to preserve that authority which God hath put upon them.
Q. 130. What are the sins of superiors?
A. The sins of superiors are, besides the neglect of the duties required of them, an inordinate seeking of themselves, their own glory, ease, profit, or pleasure; commanding things unlawful, or not in the power of inferiors to perform; counseling, encouraging, or favoring them in that which is evil; dissuading, discouraging, or discountenancing them in that which is good; correcting them unduly; careless exposing, or leaving them to wrong, temptation, and danger; provoking them to wrath; or any way dishonoring themselves, or lessening their authority, by an unjust, indiscreet, rigorous, or remiss behavior.
(these are from the revised Westminster Confession of Faith and the revised Westminster Larger Catechism, as adopted by the OPC)
The Westminster standards, as revised by the Americans, do not have some of the stronger language regarding the civil magistrate's duties, but even the American revisions have language that specifically calls for the civil magistrate to be involved in maintaining piety and justice, protecting the church of the Lord, disapproving and removing false worship, enforcing the sabbath, and providing things necessary for the souls of the populace. Likewise, the Westminster standards permit the churches, as synods, to petition the civil magistrate in extraordinary cases.
That does not mean that the American revisions of the Westminster standards require a reconstructionist view, nor does it mean that the American revisions require the views of 17th century Massachusetts. On the other hand, it does mean that those who are teaching that the civil magistrate is not called to maintain piety in the land, is forbidden to enforce the external provisions of the first table of God's law, or is not required to observe justice, are outside the confessional bounds.