Yes yes, "laws govern the actions of the weak, morals govern the actions of the strong" and all that jazz.
Of course, for that, you need a solid basis for morals, and society is wont for a broad range of moral conflictions. Or even somewhere from which to draw morals in many cases.
So agreed upon, enforced laws are the next best thing, unless you can get everyone to ascribe to the same moral code. Which, given the history of human kind... isn't likely.