What does "Which do you want — the truth or my resignation? I won’t lie for you" in this context from Asimov's book I, Robot indicate?

Question

The politician straightened out of his chair. “Then we shall see what the insides of Mr. Byerley look like. It will mean publicity for U. S. Robots — but I gave you your chance.”

Lanning turned impatiently to Susan Calvin, when they were alone. “Why do you insist–”?

And with real feeling, she responded sharply and instantly, “Which do you want — the truth or my resignation? I won’t lie for you. U. S. Robots can take care of itself. Don’t turn coward.”

“What,” said Lanning, “if he opens up Byerley, and wheels and gears fall out what then?”

“He won’t open Byerley,” said Calvin, disdainfully. “Byerley is as clever as Quinn, at the very least”

This is from Asimov's I, Robot. The politician suspected that a candidate was a robot, but Susan Calvin said that she may be able to prove him not a robot. I can't grab the meaning of this sentence: “Which do you want — the truth or my resignation? I won’t lie for you." Could you teach me?

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Answer 1

The meaning of the phrase is essentially that Susan Calvin is indicating that she will not lie in pursuit of her job. If Lanning insists that she lie, she will quit instead, her resignation. In the context of the universe, Susan suspected that Byerley was a robot.

“And the great Byerley was simply a robot.”
“Oh, there’s no way of ever finding out. I think he was. But when he decided to die, he had himself atomized, so that there will never be any legal proof. Besides, what difference would it make?”

She is not certain, but she is not willing to falsely testify that he is, or is not, because she cannot be certain and, as per the story's point, it is impossible to distinguish a properly functioning robot from a highly moral human being by behavior alone.