A lot of times within the reformed polemical debates concerning the law of God, I think that sometimes, things get lost within the carpet bombing about the logical implications regarding the respective viewpoints or what the logical implications should be.
Typically, theonomists tend to be the most obvious example of Christian activism along with Neo-Calvinists/Kuyperians. Also, typically, but not exclusively, (R)2K advocates tend to be very neutered in their approach, or even have a refusal or general reluctance at all to be an activist. And then you have folks who are presuppositional, not really theonomists, not Kuyperian, and not really (R)2K, and these folks are all over the map when it comes to activism. John Frame would be an example of this fourth category in that he seems generally pretty vocal (at least in his "Doctrine of the Christian Life"), while some others who are generally in this fourth camp tend to let their "pessimistic" eschatology justify their refusal to be involved, even through their presuppositionalism should belie this attitude of refusal.
All this to say that even if you are a presuppositionalist (as in the fourth category), this does not necessarily mean that you are a (reformed) transformationalist as a theonomist or a neo-calvinist/kuyperian is.
Transformationalism in this sense means as the gospel goes forth, people will be changed in their hearts and minds, and thus culture, politics, economics etc... will gradually conform the moral standards of law of Christ. Transformationalism can (and should) be used to focus externals such as changing legislation. However, it must properly be understood that changing legislation or changing culture isn't an ends to itself but those changes are for the purpose of reflecting God's law publicly as a context to call people to repentance and believe and have faith in the Lord Jesus Christ.
It bears repeating: it is important for transformationalists to understand that true transformation comes from the gospel changing hearts. Changed legislation or changed culture can be one of the means by which this is done (law driving to the gospel), but it can also be a result of the gospel changing hearts and behavior (gospel driving people to the law). Additionally, it should again be mentioned that any attempts to change culture or legislation are not the ends to themselves.
With this definition of transformationalism in mind, it is difficult for me to understand why all Christians are not transformationalist. Some Christians who are anti-transformationalist will say that there is an over-emphasis on worldviews, as if that somehow properly provides a rebuttal against a theonomic or neo-calvinist transformational methodology.
An overemphasis on worldviews? This is an absolutely strange statement that is being made given what the Bible says concerning the differences between those who belong in Christ and those of the world. A simple reading of 1, 2, 3 John will clearly reveal that John clearly understood that this spiritual conflict between Christians and pagans is reflected by a difference in their respective masters, worldviews (among other things) and subsequent behaviors.
First, at what point does an emphasis on worldviews become an over-emphasis? And how can we assume that that anti-transformationalist standard for over-emphasis is correct, while the theonomists' isn't? Clearly, this involves a lot of question begging and is logically absurd.
3 John 7: "It was for the sake of the Name that they went out, receiving no help from the pagans."
3 John 11: "Dear friend, do not imitate what is evil but what is good. Anyone who does what is good is from God. Anyone who does what is evil has not seen God."
2 John 7-9: Dear friend, do not imitate what is evil but what is good. Anyone who does what is good is from God. -Anyone who does what is evil has not seen God.
1 John 2:9-11: "Anyone who claims to be in the light but hates a brother or sister is still in the darkness. Anyone who loves their brother and sister lives in the light, and there is nothing in them to make them stumble. But anyone who hates a brother or sister is in the darkness and walks around in the darkness. They do not know where they are going, because the darkness has blinded them."
1 John 2: 15-17: "Do not love the world or anything in the world. If anyone loves the world, love for the Father is not in them. For everything in the world—the lust of the flesh, the lust of the eyes, and the pride of life—comes not from the Father but from the world. The world and its desires pass away, but whoever does the will of God lives forever."
1 John 3: 9, 10: "No one who is born of God will continue to sin, because God’s seed remains in them; they cannot go on sinning, because they have been born of God. This is how we know who the children of God are and who the children of the devil are: Anyone who does not do what is right is not God’s child, nor is anyone who does not love their brother and sister."
1 John 4: 2,3: "This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world."
1 John 5:18, 19: "We know that anyone born of God does not continue to sin; the One who was born of God keeps them safe, and the evil one cannot harm them. We know that we are children of God, and that the whole world is under the control of the evil one."
Even just a cursory glance should show that John labors to tell his audience that there is in fact a distinct contrast between those who are in Christ, and those who are in the world. This difference is due to our union with Christ, while those in the world do what is evil and has not seen God (2 John 9), are still in darkness (1 John 2: 9-11) etc... All of these verses that I quoted can be thought of as differences in worldview and one's subsequent actions/behavior based on his worldview. So, to disparage someone for an "over-emphasis" on contrasting the Christian worldview to the secular worldview should be really be seen as quite inconsistent with the sharp contrasts that John works hard to delineate.
Of course, as you pull the logic train backwards and forwards, this delves into other issues involving the ontological Trinity as the true theological axiom of presuppositionalism, and the derivative concept (yet still foundational in certain ways) of the worldview.
Different situations call for different emphasis in your apologetical methodology. In John's letters, the ontological Trinity is of course assumed but not directly dealt with, and so what is emphasized in the letters is the derivative contrast between a man who has union with Christ (1 John 4:2,3), his resulting worldview based on Christ (1 John 5:19) and his subsequent actions that he commits based that worldview (1 John 3:9, 10) vs. a man who is not of God.
What does this have to do with (reformed) transformationalism?
We clearly can see from this that there is a sharp spiritual (1 John 3:9, 10), moral (1 John 5:18, 19), and ethical (1 John 2:15-17) antithesis between the Christian and the non-Christian.
We clearly can see that the God-hating (Rom 1:30) presuppositions of natural man lead him to sin. We know that sin is breaking of the law of God (1 John 3:4).
We know that it is the law that provides the proper context for the gospel (and vice versa). We are saved from the curse of the law and God commands us to repent of our disobedience to Him and the law and to submit to him (Acts 2:38). By implication, when in Christ, we submit to his law for our sanctification (Jas 2:8).
We also know that God commands his people to believe in His Son. 1 John 3:23: "And this is his command: to believe in the name of his Son, Jesus Christ, and to love one another as he commanded us."
Now then, does God call only on Christians to believe in Him and to repent of their sins (law-breaking)? Or by extension, is He calling on the entire world to believe and repent?
We should clearly understand that it is the latter. If He is commanding the church to believe in Jesus, He is also commanding the rest of humanity to believe in Christ as well.
So, as we Christians go out and evangelize, we not only tell people about Christ, but we also tell them about the need to repent of their sins (1 John 3:4) because they have broken His law and to sin no more. On a large scale, as more and more people become converted, they would repent of their sins and change their behavior personally, and their extended behavior as it delves into other areas such as the legislative process and through the arts and general culture.
This is what true gopsel centered transformationalism should entail and one that every Christian, no matter what polemical stripe he is, should be praying for. Sadly, we know that this isn't the case. But even through this, I know that God will accomplish His will, even with the obstinate and ignorant sheep that we all are.
Jesus, may your will be done and please come back soon!