Placidity came back to Spade's face and voice. He said reprovingly: "You know I can't tell you that until I've talked it over with the client." (2.91)
When Polhaus asks Spade for his client's identity, Spade claims that he can't give that information up without violating client privileges. Is this a sign of Spade's professional ethics or is he simply trying to hide behind that to avoid answering Tom's questions?
"Show me," he ordered. "I'm willing to help you. I've done what I could so far. If necessary I'll go ahead blindfolded, but I can't do it without more confidence in you than I've got now. You've got to convince me that you know what it's all about, that you're not simply fiddling around by guess and by God, hoping it'll all come out all right somehow in the end." (6.75)
Spade is willing here to do his best to help out his client (in this case, Brigid O'Shaughnessy). But he still insists on having at least an inking of an idea what he's being hired to do. The fact that Brigid gives Spade so little to go on is asking quite a lot of him.
"I'm not holding out. I gave it to you straight. I'm doing a job for him, but he's got some friends that look wrong to me and I'm a little leery of him." (14.48)
Luke, the house detective at Cairo's hotel, insists that he's telling Spade the whole truth. As one of the few honest characters in the novel, Luke seems to genuinely want to help Spade out, and the information he gives Spade turns out to be accurate.
"My clients are entitled to a decent amount of secrecy. Maybe I can be made to talk to a Grand Jury or even a Coroner's Jury, but I haven't been called before either yet, and it's a cinch I'm not going to advertise my clients' business until I have to." (15.16)
Spade upholds his professional code of ethics here by refusing to divulge information about his clients without their permission. Is it morally acceptable for Spade to protect his clients' secrecy even if it means he's harboring a criminal?
"Now if you want to go to the Board and tell them I'm obstructing justice and ask them to revoke my license, hop to it. You've tried it before and it didn't get you anything but a good laugh all around." (15.18)
Spade responds to the District Attorney's threats by telling him to get his license revoked. But until then, Spade plans on doing whatever is in his client's best interests, even if means making the police unhappy.
"I've got nothing to tell you or the police and I'm God-damned tired of being called things by every crackpot on the city payroll. If you want to see me, pinch me or subpoena me or something and I'll come down with my lawyer." (15.20)
Spade's code of honor keeps him from revealing his client's personal information, but he has to take a lot of flack for it. The police are mad at him, the District Attorney is pressuring him, even Spade himself is getting tired of being called names. But he sticks to his guns, and we give him kudos for that.
"Well, what the hell? Am I supposed to run around after my clients begging them to let me help them?" (16.21)
Spade isn't always happy having to stick to his principles and his clients don't always make it easy for him to help them, either. But the whole point of having principles in the first place is to follow them even when people try to force you to change. And lucky for Spade, he has a stubborn streak that keeps him from caring what people think of him.
"You're sore because she did something on her own hook, without telling you. Why shouldn't she? You're not so damned honest, and you haven't been so much on the level with her, that she should trust you completely." (16.26)
Effie calls Spade out for feeling sore at Brigid for not telling him everything. Effie reminds Spade that he hasn't been 100% on the level with her either. The fact that Spade is honest 24/7 suggests that within his code of principles, he still leaves himself room to bend the rules.
He sat up straight, put the envelope aside—on the sofa—and addressed Gutman: "We'll come back to the money later. There's another thing that's got to be taken care of first. We've got to have a fall-guy. […] The police have got to have a victim—someone they can stick for those three murders." (18.24)
Spade insists that Gutman has to give him a "fall guy" to give to the police, but is this an ethical suggestion? If Spade is supposed to be a man of principles, is he violating his moral code by trying to find someone to pin both murderers on? Granted, Wilmer did kill Thursby, so he's guilty of one of the murders. But we find out later that Brigid is the one who killed Archer. So is Spade's demand to have a scapegoat, someone to take blame, reveal that he's really only concerned about making sure he doesn't get into trouble?
"There's ample evidence of his guilt, sir. Both men were shot with those weapons. It's a very simple matter for the police-department-experts to determine that the bullets that killed the men were fired from those weapons. You know that; you've mentioned it yourself. And that, it seems to me, ample proof of his guilt."
"Maybe," Spade agreed, "but the thing's more complicated than that and I've got to know what happened so I can be sure that the parts that won't fit in are covered up." (19.32)
Gutman has finally agreed to use Wilmer as the scapegoat, but Spade has to make sure he's got the details straight to tell the police. Here, we see that Spade is actively trying to "cover up" the parts of the story that aren't true. Is Spade bluffing here to trap Gutman? Or does Spade really intend on turning Wilmer in for both murders, even though Spade knows that Wilmer is only responsible for one them?
"When a man's partner is killed, he's supposed to do something about it. It doesn't make any difference what you thought of him. He was your partner and you're supposed to do something about it. Then it happens we were in the detective business. Well, when one of your organization gets killed it's bad business to let the killer get away with it. It's bad all around—bad for that one organization, bad for every detective everywhere." (20.80)
Spade makes quite a pretty speech at the end of the novel to explain to Brigid why he's turning her over to the police. It seems that Spade does ultimately uphold his code of principles by capturing Archer's murderer. But there are moments in his speech when we can sense that Spade is operating at least somewhat on self-interest. Spade says that it's "bad business" letting the killer get away, so does this mean that Spade can't afford to let his reputation get sullied by coming to the police empty-handed? Is Spade more concerned about his detective business than his love for Brigid?