Known as one of Shaw's "discussion plays," Major Barbara is primarily structured through a series of conversations on morality, religion, and social engineering. The primary topic of discussion is what Shaw identifies in the preface as the "Gospel of Saint Andrew Undershaft," that is, the gospel that would promise society's redemption.
Undershaft's gospel is organized around the apotheosis of the millionaire and, more specifically, the military industrialist. As the characters will come to realize, the world is not in God's power but in the power of the military industrialist. With money and gunpowder, Undershaft participates in the power that reigns over Europe, the power that determines the course of society. This re-organization of society, rather than one's faith in a religious doctrine, provides the means of salvation. For Undershaft, man does not need redemption from sinfulness but from the material abjection of poverty, hunger, and sickness. The growth of Christian virtues rests fundamentally on man's material security. Undershaft wants nothing to do with a religion that abjures warfare and wealth. These evils are the necessary means by which man can be saved.
Though initially resistant, the democratic Cusins will soon convert to Undershaft's gospel and become his successor. Barbara will return to the Salvation Army with this gospel as well, recognizing that the necessary dialectic between good and evil means that the work of salvation requires the pact with the Devil. They both come to realize Undershaft's power upon the demonstration of his authority over the Salvation Army, a purchase that reveals how all work of salvation is indeed contingent on those who hold the money and gunpowder.
Unlike Undershaft, Cusins takes up the armory in the name of a love for the people. Through the armory, he will abandon his anachronistic and intellectualizing studies and make power for the contemporary world, a power accessible to the masses and that forces the "intellectual oligarchy" to exert itself for the general good. He too exalts the arm as the force that stands to destroy all forces and determines the course of the world.
Undershaft's philosophy also organizes itself around a notion the great man's "will." This will comes into being through the agonistic struggle between men. As Undershaft proclaims, a sacred commandment, "Thou shalt starve ere I starve," sets him on the path to greatness. Through a murderous struggle with others, Undershaft realizes his will and desire. Thus his "bravest enemy" is his best friend, a rival who keeps him "up to the mark." Over and against Christian ideals of human brotherhood, the recognition Undershaft demands from his neighbor is not love but obedience and respect, a bending to his will. Again, the struggle he stages with others is decidedly violent. Those who do not submit to his desire must die.
Such killing in the name of the will does restrict itself to those who stand in the way of the great man's desire, but extant social structures, institutions, and ways of thinking as well. Killing is the means by which the moralist's "ought" becomes a "shall"; it is the "only way of saying Must." Only the murderous command can inaugurate the new that follows necessarily according to the will of the great man. Until he achieves his will, he is menace to civilization; upon its realization, he becomes its benefactor. Thus, the great man makes history.
Major Barbara is structured by a contest between father and daughter for the other's soul and the path of salvation. Each agrees to visit the other's workplace and allow the other to attempt their conversion. Undershaft's visit to the Salvation Army shelter takes place in Act II; Barbara goes to the armory with her family in Act III.
As discussed in the preface, Shaw's portrait of the shelter is fundamentally a critique of the Salvation Army's flaws. One of the many criticisms Shaw underlines, for example, is that the Army forces its clientele to pander to the saintliness of its workers. In this sense does the work of the Army have less to do with the condition of the poor than the narcissism of its officers. More importantly, the Army fails to realize that man does not need redemption from sinfulness but from the material abjection of poverty, hunger, and sickness.
Unlike the shelter, Perivalee Saint Andrews appears as a paradise of social engineering. Undershaft has redeemed his men more successfully than preaching ever could by eliminating poverty. He does not do so for the love of the masses. Certainly Undershaft provides for their comfort to assure his company's productivity. He also, however, considers poverty the worst of man's crimes. For Undershaft, the "crime of poverty" is a crime committed against society by the poor themselves. The poor, appearing as abject masses from some paranoid fantasy, "kill" society's happiness, forcing the ruling class to eliminate its liberties and organize "unnatural cruelties" to keep them in check.
Thus Undershaft will pit himself against poverty in the name of order and cleanliness. Indeed, for Undershaft, order and cleanliness are categorical imperatives of sorts—they justify themselves. Though the realization of these imperatives would ostensibly benefit the masses, we can readily imagine how they might come at their expense as well. Simply put, the institution of order and cleanliness easily means the elimination of the disorderly and unclean. Note in this respect Undershaft's chilling invocation of the Salvation Army's motto in Act I: "My sort of blood cleanses: my sort of fire purifies."
The Undershaft tradition is a tradition of foundlings, each Undershaft passing the firm onto a foundling who adopts the namesake of the parish—Saint Andrew's—where the firm's founder was discovered. This tradition demands Stephen's dispossession and Undershaft's estrangement from his family.
Within Undershaft's dogma, the foundling figures as a willful, self-made superman, a man whose thoughts and actions remain free from the chains of familial and class convention. The foundling is thus poised to surrender himself to the Undershaft name and carry forth its gospel of revolution, to destroy the old and inaugurate the new. For Undershaft, the tragedy is that the welfare state tames most of these men from birth, rendering them indistinguishable from the herd.
As Undershaft's successors, Cusins and Barbara assume the foundling's mantle. Cusins reveals the illicit origins of his birth, sheds his name, and becomes the next Saint Andrew. For Barbara, her foundling heritage means that she has no social class and thus comes "straight from the heart of the whole people". She represents the people universally and can thus serve their savior.
Certainly the most jarring shift from Acts I to II is the introduction of class- marked dialect, Cockney. Shaw's representation of the poor is at times fetishistic itself. Note, for example, how Rummy and Price are played affectionately for the audience's entertainment. Though they have long since pawned their winter clothes, the two are "stung into vivacity" by the cold, chattering vivaciously over their poor meal. Occasionally Price even breaks into a step dance.
Here one of dialect's primary functions is to set Barbara—the savior—against those who require salvation. Major Barbara figures as savior in the shelter through both her class and linguistic superiority over those around her. Barbara maintains her composure before all those around her through her impeccable dress and cool, professional manner. Moreover her return before the audience is the return of the proper, polished English of the act previous. In contrast, at his lowest, Bill's "voice and accent" will become "horribly debased." Barbara's dialect—that is, the dialect that masquerades as no dialect at all but "proper English," English as it should be—marks her as the Cockney's redeemer.
A number of objects assume crucial symbolic significance in the play. As Undershaft remarks, Cusins's ubiquitous drum, for example, symbolizes his relation to the Salvation Army. Like the drum, the Army is but an instrument for his Dionysian fervor.
Also of note are the dummy soldiers strewn about the stage in Act III. These dummies underline the omnipresence of the murders that support this utopian of Perivalee St. Andrews. It is also not for nothing that the idyllic community has also been erected in the shadow of explosives. As we recall, for Undershaft these murders distinguish the military industrialist from common "moralist," establishing the former as a man of action. Within Undershaft's schema, such murders are necessary to society's redemption.