Sometimes Barth speaks of the unique importance of the doctrine of justification in such a way that one might think he understood its role in theology in much the same way the Reformers did.
There is no part of dogmatics, no locus, where we can treat it lightly. At every point we are dealing with the one high Gospel. What we can and must say is that in the doctrine of justification we are dealing with the most pronounced and puzzling form of this transition because we are dealing specifically with the question of its final possibility. … But in the doctrine of justification we have to do with the original centre of this crisis [between holy God and sinful man], and to that extent with its sharpest form, with what we can describe provisionally as the crisis which underlies the whole. If we find it running through the whole with all kinds of repetitions and variations, at this point where we grapple with the peculiar difficulty of it, it has to be seen and handled as the main theme—the question: How am I to lay hold of a gracious God?
Nevertheless, Barth distinguishes himself from the Western Protestantism of his own day and his contemporary interlocutor Ernst Wolf by allowing the article of justification to be one among many aspects of the gospel, not necessarily the Word of Gospel itself.
There can be no question of disputing the particular function of the doctrine of justification. And it is also in order that at certain periods and in certain situations, in the face of definite opposition and obscuration, this particular function has been brought out in a particular way, that it has been asserted as the Word of the Gospel, that both offensively and defensively it has been adopted as the theological truth. There have been times when this has been not merely legitimate but necessary, when attention has had to be focused on the theology of Galatians and Romans (or more accurately, Rom 1-8). … [e.g. Augustine] … But in theology it is good to look beyond the needs and necessities of the moment, to exercise restraint in a reaction however justified to be constantly aware of the limits of the ruling trend (however true and well-founded it may be). … In the Church of Jesus Christ this doctrine has not always been the Word of the Gospel, and it would be an act of narrowing and unjust exclusiveness to proclaim and treat it as such. … [I]t relates only to one aspect of the Christian message of reconciliation. … [I]n the true Church of Jesus Christ the formulated recognition and attestation of this truth may withdraw, it may indeed be more or less hidden behind other aspects of the Christian message, without it being right and necessary to draw attention to its absence, to believe that its truth is denied and the unity of the Church is broken. … The Christology of Paul is more than simply an argument for his doctrine of justification.
Several observations of Church history are set forth by Barth at this juncture to compliment his position and help set this doctrine in perspective. For example, he raises the point that the early church saw no explicit treatment or emphasis on the doctrine of justification, and the development that took place in the writings of Augustine “was something which belonged specifically to the Western Church. The East was much less interested in the contrast between sin and grace than in that between death and life, between mortality and immortality.” He also claims that John Calvin’s thought was controlled and organized by “the development and formation of the Christian life and therefore of sanctification,” and was even “overshadowed” by his doctrine of predestination which “plumbed the matter even further.” He concludes: “One thing is certain—that if the theology of Calvin has a centre at all it does not lie in the doctrine of justification.”
Even Martin Luther himself, Barth argued, always had a twofold emphasis in his teaching: one having to do with the once-and-for-all work of Christ and another having to do with the righteousness which is given to man in the Spirit’s work of new birth. Luther insisted that both justification and sanctification are in need of being properly maintained. “If either of them is forgotten or neglected in favour of the other, this will inevitably involve the corruption either of faith or of its power and fruit.” Pointing out that Luther’s own understanding of justification was a theolgia viatorum (being reformed and developed throughout his life), he remarks, “Luthernaism old and new followed the direction of Luther—or at least the older Luther—when, like Calvin and Calvinism, it refused to centre its theology upon the one article of justification.”
Pietism and Methodism also put their chief emphasis on aspects of reconciliation which Barth argues cannot be subsumed under the narrow category of justification. Barth’s alternative form of thought was, he hoped, more balanced, a midway between placing too much emphasis and importance on the article of justification on the one hand (as if it were the gospel and to the neglect of other equally important aspects of reconciliation) and relegating it to secondary or marginal status on the other.
All honour to the question: How can I find a gracious God? But for too long it has been for Protestantism—at any rate European and especially German Protestantism—the occasion and temptation to a certain narcissism, and a consequent delay in moving in the direction we have just indicated. The articulus stantis et cadentis acclesiae is not the doctrine of justification as such, but its basis and culmination: the confession of Jesus Christ, in whom are hid all the treasures of wisdom and knowledge (Co. 2:3) … The problem of justification does not need artificially to be absolutised and given a monopoly.
Alister McGrath speculates that such a demotion of the importance of the doctrine of justification in Barth’s theology results from his “essentially supralapsarian understanding of the Fall” and reflects a broader theological trend:
[T]he onset of Reformed orthodoxy saw the starting point for theological speculation shifted from the concrete event of the justification of the sinner in Christ to the divine decrees of election and reprobation. … As a result, justification is accorded a place of low priority in the ordo salutis, in that it is merely the concrete actualization of the prior divine decision of election. Barth approximates more closely to the theological method of Reformed orthodoxy than to that of Calvin.
Although Barth saw himself in basic agreement with the Reformers, he ultimately believed that the level of importance Luther placed on this doctrine was driven largely by their cultural context.
 Ibid., 522-24.
 Ibid., 524.
 Ibid., 525.
 Ibid., 525-26.
 Ibid., 526.
 Ibid., 526-27.
 Ibid., 527-28.
 McGrath, Iustitia Dei, 400. cf. Alister McGrath, “Karl Barth and the articulus iustificationis,” Theologische Zeitschrift, vol 39 (1983): 349-361.