The late John Robbins wrote:
“One consequence of this denial of the covenant of works is that if Adam was not a party to the covenant of works, as these men assert, then neither was Christ, the Second and Last Adam.
Therefore, Christ could not, did not, and was not supposed to pay the debts of, and earn salvation for, his people. As the Second and Last Adam, Christ did not by his active and passive obedience fulfill the Law of God, pay the debts of his people, and merit their salvation. Thus the denial of the covenant of works is an attack on the justice of God: on the imputation of Adam’s sin to his children, on the active obedience and work of Christ, on the imputation of Christ’s active obedience and righteousness to believers. By denying that Adam and Christ, as federal heads of their respective races, were subject to the covenant of works before the court of God’s justice, not his grace, each Adam being required to fulfill the terms of the covenant, one failing miserably, and the other succeeding perfectly, the Neolegalists put all believers on probation, and make their salvation depend on their own evangelical obedience” (John W. Robbins, Pied Piper).
What does it MEAN for the First Adam to be a “party to the covenant of works”? In the words of Blackguard Boettner, it meaneth precisely this:
“Adam was given a most favorable opportunity to secure eternal life and blessedness for himself and his posterity” (Boettner, The Reformed Doctrine Of Predestination, p. 236).
Robbins’ argument (whether he realized it or not) is that IF the First Adam is precluded from this “favorable opportunity” to usurp the redemptive throne of Jesus Christ & crown himself “king,” THEN the Second & Last Adam IS ALSO precluded from the “opportunity” to secure eternal life for His people and to sit down as King upon His redemptive throne of glory (cf. Hebrews 9:11-12, 10:11-14). Or, Robbins’s argument could be stated in this way:
IF Adam is precluded from “a most favorable opportunity” to receive idolatrous worship, THEN Christ IS ALSO precluded from the “opportunity” of receiving power and riches and wisdom and strength and honor and glory and blessing (cf. Revelation 5:12).
In brief, Robbins’ “if-then” reasoning is a blatant non sequitur.