If you leave because the negotiation didn't get you enough, and the company feels a pinch as a result, I think that would get the manager more credibility for p

If you leave because the negotiation didn't get you enough, and the company feels a pinch as a result, I think that would get the manager more credibility for proactively trying to head off the loss of talent. Besides, if you negotiate a raise and then leave, it means that they don't have to pay you that raise after all, right?