One of the great debates in the nineteenth-century American Presbyterian church centered around Roman Catholic baptism. As large numbers of people were emigrating to the United States from Roman Catholic countries, and as some of those people sought membership in Presbyterian congregations, an old question pressed itself anew on the church—“Is Roman Catholic baptism valid?”
Presbyterians realized that to answer this question they had to answer a more basic question—“is Rome a ‘true part of Christ’s visible church’”? If Rome is a true church, then her sacraments are valid, and Presbyterians should acknowledge that fact when they receive someone into her membership who had been baptized in the Roman Catholic Church. But if Rome is not a true church, then her sacraments are not valid. In that case, someone who had received Roman Catholic baptism would not have received Christian baptism. That person would need to be baptized upon reception into the Presbyterian church.
Presbyterians debated the validity of Roman Catholic baptism throughout the nineteenth century and continue to debate it today. The underlying question remains the same—Does Rome have the marks of the true church? To answer that question, two questions are in order. First, what are the marks of the church? Second, does Rome bear those marks?
What are the marks of the church? At first glance, it appears that the Reformed tradition disagrees with itself here. The Westminster Confession of Faith says that “the visible church … consists of all those throughout the world that possess the true religion; and of their children” (25.2). There is one mark of the church—“possessing the truth.” But the Belgic Confession identifies three marks of the church—“the pure doctrine of the Gospel,” “the pure administration of the sacraments,” and “church discipline” (Art. 29). So, is there one mark or are there three marks? Francis Turretin pronounced this a distinction without a difference—“it is all the same thing.” If a church confesses the true religion, then she will administer the sacraments and discipline in accordance with the Word of God.
Does Rome bear this mark of the church? The way to answer this question is not to scan the Twitter feed of Pope Francis, nor is it find out what the priest of the local Roman Catholic parish preached in his Sunday homily. To find the answer, one must consult what Rome has officially confessed. One of the most important defining statements of the Roman Catholic Church is that of the Council of Trent, which met from 1545 to 1563. The Decrees and Canons of Trent are the official response of Rome to the Protestant Reformation. They offer an especially revealing look at Rome’s institutional reaction to the doctrine of justification by faith alone.
Trent’s Decree on Justification amounts to a positive statement of Rome’s understanding of justification. It is in its Canons on Justification that Trent expressed pointed disagreement with views that Rome believed the Reformers taught. Trent then proceeds to condemn those views—“let him be anathema” (accursed). Some of these Canons are especially revealing.
Can. 7. If anyone says that all works performed before justification, no matter how they were performed, are truly sins or deserve God’s hatred; or that the more earnestly one tries to dispose himself for grace, the more grievously he sins, let him be anathema.
Can. 9. If anyone says that the sinner is justified by faith alone in the sense that nothing else is required by way of cooperation in order to obtain the grace of justification and that it is not at all necessary that he should be prepared and disposed by the movement of his will, let him be anathema.
Can. 11. If anyone says that men are justified either by the imputation of Christ’s justice alone or by the remission of sins alone, excluding grace and charity that is poured into their hearts by the Holy Spirit [cf. Rom 5:5] and inheres in them, or also that the grace that justifies us is only the favor of God, let him be anathema.
Can. 12. If anyone says that justifying faith is nothing else than confidence in the divine mercy that remits sins on account of Christ or that it is this confidence alone that justifies us, let him be anathema.
While it is hard to see the Reformers speaking of “works,” “faith alone,” or “imputation” in precisely these terms, there is enough of the Reformers’ doctrine here to merit the conclusion that Rome knowingly anathematized the Reformation’s doctrine of justification by faith alone.
It is not simply that the Roman Catholic Church tolerates error, even grave error, within her bounds. Rather, Rome has knowingly and officially anathematized enough of the gospel to forfeit any right to be recognized as part of the visible church. Furthermore, Rome has not rescinded these anathemas; they remain the official stance of Rome today.
One could take up at this point a host of other questions. Does Rome faithfully administer the Lord’s Supper? Does Rome properly administer church discipline? Are her clergy genuine officers of the Christian church? But these questions all lie downstream of the most important question—what has Rome done with “the true religion”? There can be no doubt what it has done. It has pronounced a curse upon the gospel proclaimed by Martin Luther, John Calvin, and their theological descendants.
This is in no way to question that Rome has preserved much truth within her bounds, nor is it to doubt that there may be genuine Christians within the Roman communion. Neither is it to deny that Roman Catholics have proven welcome co-belligerents with Protestants in some of the great cultural struggles of our day. But clear lines need to be drawn to safeguard the integrity of the biblical gospel that we believe, proclaim, and love.
 For a summary of the actions of the Presbyterian Church in this time period, see J. Aspinwall Hodge, What Is Presbyterian Law As Defined By Church Courts? (7th ed.; Philadelphia: Presbyterian Board of Publication, 1894), 84–5, and J. D. Leslie, Presbyterian Law and Procedure in the Presbyterian Church in the United States (Richmond: Presbyterian Committee of Publication, 1930), 303–4.
 The quoted language is that of the 1871 General Assembly of the PCUS, as cited at Leslie, Presbyterian Law and Procedure, 304. This particular Assembly declared Rome to be no true part of the visible church. Assemblies of the American Presbyterian church had been addressing this question since at least 1835.
 It is important to stress here that what is in view is not rebaptism. All Reformed parties agree that “the sacrament of Baptism is but once to be administered unto any person” (WCF 28.7). Those who deem Roman Catholic baptism invalid believe that a person who had received Roman Catholic baptism had never truly received Christian baptism in the first place.
 If Rome is not a true church, as we will argue below, then her baptism is not Christian baptism. For that reason, I concur with those Presbyterians who do not recognize Roman Catholic baptism to be Christian baptism.
 James Bannerman, The Church of Christ (2 vols.; 1868; repr. Edinburgh: Banner of Truth, 1960), 1:62.
 Francis Turretin, Institutes of Elenctic Theology, trans. James T. Dennison, Jr. (3 vols.; Phillipsburg, NJ: P&R, 1992–7), 3:87.
 For the full text, in Latin and English, of Trent, see Heinrich Denzinger, Compendium of Creeds, Definitions, and Declarations on Matters of Faith and Morals, eds., Peter Hünermann, Robert Fastiggi, and Anne Englund Nash (43d ed.; San Francisco: Ignatius, 2012), 368–413.
 The Latin formula “anathema sit” concludes each of these canons.
 In reading through Trent’s other Canons on Justification, however, one gets the sense that they understood the Reformation to be teaching antinomianism (see Canons 18, 19, 20, 21).
 Nor could she rescind these anathemas without fatally injuring her claim to infallibility.