I feel like re-upping this one.

I generally dislike metaphors when applied to policy discussions. They very rarely, and possibly never, illuminate more than they obfuscate. The “carrot and stick” metaphor used so often in nonproliferation discussions is especially poor for a few reasons, not least of which is that governments dislike being equated with farm animals. Moreover, as is the case with other metaphors, “carrot and stick” can be interpreted differently by different people.

As an illustrative example, I give you the great Malcolm Tucker (Warning: NSFW):

It’s a bit heavy on the negative incentives approach, particularly as compared to the metaphor’s typical use.