I don’t imagine this is going to phase Obama much. It’s kinda like house buying, I’d imagine - you make an offer for a house and the seller thinks it’s too low, so the seller makes a counter offer that you think is too high. Eventually, you either find an acceptable price that both of you like or you start looking at other houses.

Obama has attempted to make an appeasement and Iran is trying to get more appeasement. If Obama doesn’t offer that additional appeasement, Iran may just decide to take what they can get. Or they might not.

That Iran said that Obama’s offer showed “the system of domination [has] failed” is like the house seller saying “your offer was a bad one and the theory that led to you concluding it was a good one has failed”. Maybe it has, maybe it hasn’t - maybe Iran will take it if they figure they can’t get anything else, or, if Iran won’t take it, then, from their perspective, it may have been a bad deal.

To say that this means that all Iran understands is force seems a bit like jumping the gun.