My father says, "If you agree to do something, then you had better do it."
I think that's pretty simple. I wish the whole world thought that way. Just think, countries and people might be more careful what they say and honor would be a commonality. The US would have to abide by it's agreements (like NAFTA), and other countries could be taken at face value as well (like EVERY country).
Then again, maybe it's too good to be true, but it doesn't mean that the people of the world can't follow good advise for themselves.