SERGEANT: […] Takes a war to get proper nominal rolls and inventories—shoes in bundles and corn in bags, and man and beast properly numbered and carted off, cause it stand to reason: no order, no war. (I, 24-27)
Well, that says it. The sergeant's view of war is that it brings order to society, while peace is just a time of stagnation before the next war comes. Is that so different from what Mother Courage herself believes? She might blame the war for taking her children's lives, but the war also establishes the social order in which she makes her living.
SERGEANT: Halt! Who are you with, you trash?
THE ELDER SON: Second Finnish Regiment.
SERGEANT: Where's your papers? (I, 68-70)
Who is he calling trash? Mother Courage enters the play in a scene of interrogation, a meeting point between her family and the rules of the military. Here, before we even know Eilif's name, the sergeant is asking him which regiment he belongs to.
MOTHER COURAGE: Talk proper to me, do you mind, and don't you dare say I'm pulling your leg in front of my unsullied children, t'ain't decent, I got no time for you. My honest face, that's me licence with the Second Regiment, and if it's too difficult for you to read there's nowt I can do about it. Nobody's putting a stamp on that.
RECRUITER: Sergeant, methinks I smell insubordination in this individual. What's needed in our camp is obedience. (I, 97-98)
Don't try this one at the airport. Mother Courage's refusal to stand down when the sergeant and recruiter demand her paperwork is an obvious act of "insubordination." But it's clear she's not out to make trouble. Later, she is tricked into trying to sell the sergeant a belt buckle, and the recruiter convinces Eilif to join the army. This establishes a precedent for Mother Courage's tendency to care more about business than resistance to authority.
EILIF: […] I put it on a business footing from the start, told them 'Twenty florins a head's too much. I'll give you fifteen'. As I was meaning to pay. That threw them, and they began scratching their heads. In a flash I'd picked up my sword and was hacking 'em to pieces. (II, 119-123)
Looks like Eilif picked up a thing or two from his mother. Eilif's clever trick to steal cattle from peasants relies on breaking the rules of exchange. He pretends to pay them for the cattle, then at the last second, he surprises them with an attack. Later, Eilif will lose his life for pulling the same kind of stunt. The rule breaking he performs in tricking the peasants already foreshadows the rule breaking for which he gets punished.
MOTHER COURAGE: […] Stealing Yvette's boots! She's wrecking herself for money. That's understandable. But you'd do it for nothing, for pleasure. What did I tell you: you're to wait til it's peace. No soldiers for you. You're not to start exhibiting yourself till it's peacetime. (III, 386-390)
Talk about suffocating. Mother Courage is really into regulating Kattrin's sex life. Here, she compares Kattrin to Yvette. When Yvette sleeps with men, she does it for money, which means she's playing by an established rule that keeps her safe. But if Kattrin wants to do it "for nothing, for pleasure," then she's heading into territory that isn't bounded by any economic rules, and that spells danger in this world.
MOTHER COURAGE: […] Thank the Lord they're corruptible. After all, they ain't wolves, just humans out for money. Corruption in humans is same as compassion in God. Corruption's our only hope. Long as we have it there'll be lenient sentences and even an innocent man'll have a chance of being let off. (III, 644-649)
Corruption is organized rule-breaking. When it becomes the norm, it's pretty dependable. And at least for Mother Courage, it's a rule that's a lot more dependable than something that requires faith, like God.
MOTHER COURAGE: Oh I see, you're hungry. Last year that general of yours ordered you all off roads and across fields so corn should be trampled flat; I could've got ten florins for a pair of boots s'pose I'd had boots and s'pose anyone'd been able to pay ten florins. Thought he'd be well away from that area this year, he did, but here he is, still there, and hunger is great. I see what you're angry about. (IV, 50-56)
Even when Mother Courage knows to play by the rules, she can still acknowledge them as absurd. She sees right through the young soldier's complaint in Scene IV, recognizing the real source of his anger. The orders he follows are not for his own good, or maybe even for anyone's good.
MOTHER COURAGE: He's sitting now. See, what did I say? You're sitting now. Ah, how well they know us, no one need tell 'em how to go about it. Sit down! And, bingo, we're sitting. And sitting and sedition don't mix. Don't try to stand up, you won't stand the way you was standing before. (IV, 85-88)
She's really on his case here. Mother Courage is determined to show the young soldier that he's still following all the rules even when he thinks he's rebelling. She thinks his anger is trivial, because he can't see beyond his own particular case in order to grasp the systemic problem.
MOTHER COURAGE: Then I heard a tit Chirp: Wait a bit! And you'll be marching with the band In step, responding to command And striking up your little dance: Now we advance. And now: parade, form square! Then men swear God's there— Not the faintest chance! (IV, 94-110)
Mother Courage's song suggests a time in her life when she had to learn that life is about playing by the rules. That time was clearly the onset of the war. And as for her belief in God, her song poses the following question: if everyone is already following the rules established by warfare, does God still need to exist?
THE ENSIGN: Look at her laughing at us. I'm not having that. I'll shoot her down, and damn the consequences. Fetch the harquebus. (XI, 168-170)
One thing's for sure: laughter is forbidden. Kattrin's big offense, in the eyes of the ensign, is that she ignores his orders to stop drumming and laughs in his face. And then, he himself goes against the rules by shooting her, having received no orders to do so. Kattrin's drumming is not only an act of insubordination; it breaks down the rule-governed structure of military power, and brings out the soldier's uncontrolled violence.