Kennedy: “If you promise…
Kennedy:
“If you promise me $10 and then don’t deliver do I have any moral claim against you?”
Well, yes, obviously. That’s what promises are for: keeping.
There are lots of speech-acts that morally bind you to carry something through even though breaking them doesn’t count as a violation of anybody’s rights: not just making promises but also, e.g., swearing, taking oaths, exchanging vows, making alliances, etc. By giving your word you accept a moral obligation on yourself, and by breaking it you are doing wrong. If the moral obligation is an obligation directed towards somebody else (e.g. if you exchange a vow of sexual faithfulness with me, or if you promise me some gift) then by breaking it you are specifically wronging the other party.
Of course, it is only in the case of a contract that the sort of wrong you do is a violation of rights. But violating somebody’s rights is hardly the only way that you can do wrong by her.