Was Machen Wrong Not to Appeal to Union?

Writing on Gal. 2:19 (“For I through the law died to the law, that I might live to God”), a verse smack dab in a passage where Paul talks a lot about being “in” Christ, Machen writes the following:

The law . . . led men, by its clear revelation of what God requires, to relinquish all claim to salvation by their own obedience. In that sense, surely, Paul could say that it was “through the law” that he died to the law. The law made the commands of God so terribly clear that Paul could see plainly that there was no hope for him if he appealed for his salvation to his own obedience to those commands.

This interpretation yields a truly Pauline thought. But the immediate context suggests another, and an even profounder, meaning for the words. The key to the interpretation is probably to be found in the sentences, “I have been crucified together with Christ,” which almost immediately follows. “The law,” Paul probably means, “caused me to die to the law, because the law, with its penalty of death upon sins (which penalty Christ bore in our stead) brought Christ to the cross; and when Christ died I died, since he died as my representative.” In other words, the death to the law of which Paul here speaks is the death which the law itself brought about when it said, “the soul that sinneth it shall die.” Christ died that death, which the law fixes as the penalty of sin, when He died upon the cross; and since He died that death as our representative, we too have died that death; the penalty of the law is for us done away because theat penalty has been paid in our stead by the Lord Jesus Christ. Thus our death to the law, suffered for us by Christ, far from being contrary to the law, was in fulfilment of the law’s own demands. We are free from the penalty of death pronounced by the law upon sin not because we are rebels against the law, but because the penalty has been paid by Christ. (Machen’s Notes on Galatians, p. 159)

It is striking that Machen, a none too shabby Pauline scholar, preferred to use the language of representation or substitution rather than union with Christ. And instead of seeing union as the sub-text, Machen interprets this passage in what appears to be straightforwardly forensic categories.