After a course this semester in International Law (well, technically "The Israel-Arab Conflict", but from the perspective of an international law analysis) and another in Jurisprudence, I have more or less come to the following conclusion: Public International Law is the most utter load of malarky that I have yet encountered. Or, to put it in a slightly less incendiary way, it is all very well and good and bears absolutely no resemblance to "law" in its official senses.
Obviously, the question of what is law is a complicated and hotly debated one, which I would prefer not to get into for two reasons: 1)It would involve a lot of typing and 2)I haven't actually finished studying for the test that we have to know all that for. But if you look at some of the most basic modern thinkers on the subject, it's hard to see how exactly international law fits in.
Austin, for example, defines law as norms accompanied by sanctions. That which will be punished, is a law. International law, in contrast, is backed by no official group with any power. The UN, which might theoretically be viewed as the sovereign enforcing these rules, fails to do so under almost all circumstances. Furthermore, the UN Security Counsel, the only body with the authorization to employ force, may do so whenever it identifies a likely breach of international peace or some such, which means that it is not predicated on any violation of international law per se.
H.L.A Hart modified Austin's claim to define law as anything that is recognized as legitimate, legally, from the perspective of those subject to it; law that is not enforced may still manage to be law, as long as all or most of those to whom it is addressed regard is as binding. Just about no state of which I am aware has ever avoided doing something that they otherwise would prefer to do based simply on the logic that it is against international law. They may not want the sanctions that other countries may or may not impose, but again, such sanctions may and are applied without regard to whether the actions officially violate international law or are simply dangerous/annoying/immoral. International law, in and of itself, is not really regarded as authoritative by those to whom it applies.
My personal favorite definition of law is that of Holmes (and not just because the man rocks): Law is simply what the bad man would care to know- how likely is action x to lead to a negative consequence in the form of the state's wielding its power against me if I do it? I think that it is pretty clear from the reality that the bad men of international law- and there are plenty- are pretty relaxed about the legal consequences of their actions. International law does little to nothing to deter them and therefore, does not actually exist.
The above is perhaps a little harsh. It would be more fair to say that international law does not exist according to any modern definitions of law. In fact, it seems quite similar to more classic definitions, which failed to make the sharp distinction between morality and law. International law, as a vague systems of norms that are neither enforced nor defined by any authoritative body, but which are intended to reflect basic universal standards of morality, really fit well with Natural Law theorists. However, in that case, international law is nothing more than one attempt to define morality, as it relates to the actions of nations towards one another, and has no more (or less) force or authority than any other of a hundred attempts to define morality, including religion, philosophy, and just about any ism. (Nor is public international law necessarily incompatible with the very new schools of thought, which tend to believe that all law is simply an arbitrary collection of guidelines aimed at preserving status quo, crushing the lower classes, and so forth. To the degree that you accept such views, international law is no less "real" than any other form of law, except perhaps, in that nobody is real effectively crushed by it. But I kind of hate those particular theories, which is why they are left in smaller-fonted parentheses.)
If that is the way that international law wants to be- and it has every right to be like that- my only real objection is that it should stop calling itself 'law' and thus prancing about in the mask of objectivity, enforcability, authority, and certainty that the title denotes in modern parlance. If we only called it "Public International Morality", I think that it would annoy me a whole lot less.