In theology, federal headship is one theory used to explain imputation—how Adam’s sin was imputed to all his descendants and how Christ’s righteousness was imputed to those who believe the gospel. According to the federal headship theory, or federalism, Adam was the federal (or representative) head of the human race; Adam chose to sin, and all of us are considered guilty, too, because he was our representative. Federal headship is seen as a possible explanation of Paul’s comparison of the roles of Adam and Christ in Romans 5:18: “As one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men” (ESV). So, Adam’s sin brought condemnation on the human race; Christ’s sacrifice brought salvation for the whole race. The idea of federal headship involves the teaching that Adam was the first representative of the human race and Christ was the second representative.
The idea of federal headship is not explicit in the Bible; that is, the Bible nowhere calls Adam our representative. Federal headship is simply a way some scholars have chosen to speak about Adam’s, and then Christ’s, involvement in the destiny of humanity. The theory is based on Paul’s argument in Romans 5 that “sin entered the world through one man, and death through sin, and in this way death came to all people, because all sinned” (verse 12). From Adam to Moses, even before the Law was given, “death reigned” (verse 14). If there was no Mosaic Law, and if “where there is no law there is no transgression” (Romans 4:15), how could Adam’s sons have been deemed sinful? Applying the concept of federal headship, we can say it was because they were part of the human race; Adam was their representative, and therefore Adam’s transgression applied to all men.
The weakness of federal headship is that it is an interpretive tool, not an explicitly biblical truth. Romans 5 does not say that Adam was the representative of the human race, only that “by the trespass of the one man, death reigned through that one man” (Romans 5:17). God never says exactly how the transference of the sin nature occurred, only that it did occur.
What we know for certain is that death entered the world through Adam’s sin. The idea of federal headship is not stated outright in Scripture, but Adam’s sin was definitely the origin of the problem, and sin was inherited by all of us through him. Then Christ came and by His sacrifice became our Savior. Thus, there is a parallel between Adam and Christ: “Just as one trespass resulted in condemnation for all people, so also one righteous act resulted in justification and life for all people. For just as through the disobedience of the one man the many were made sinners, so also through the obedience of the one man the many will be made righteous” (Romans 5:18–19).