The UN is the biggest joke in politics. It cannot diffuse crises and it cannot force nations to act for the common good. It serves only as a forum from which to posture for the camera and as a conduit for huge amounts of public money to find its way into a few personal bank accounts. The UN was deliberately set up to be impotent, and so it has been proven over and over. Nations conduct their real business between each other directly and completely ignore UN resolutions as it suits them, with no consequences. The only time UN resolutions are followed through is if nations were already going to do that anyway. At best, the UN is simply a way for the real powers to bully the weak without being held directly responsible.
It seems we share the same viewpoint.

However, they have the influence (which is mainly based on ignorance or fear) to be one hell of a pain in someone's side if he breaks their "laws," major member or not. Not to mention the fact that the major powers can "oust" one from their group and gang-up on it, with the support of just about everyone else.
The history of multinational arms reduction treaties is also no grounds for confidence. Go back and see how much good the naval treaties of the 20s and 30s did.
Indeed, but there was already a war (or conflict, if that's what you want to call it) going on, and there was no pressure from the "international community." There was already a belligerent (or two). We are at peace right now. That does change how a country acts (mostly, unless it's run by a psychopath or a total idiot). You'd want to stay out of a war as long as possible while simultaneously building your armed forces (and even using them).
Now, there is no major war/conflict between us and China, nor between us and any major opponent. The introduction of Iran could throw this off balance, but so far, it's only been limited conflict in a relatively small portion of the world.
Today's situation is much more like it was back then than it is like the Cold War. When it was just 2 superpowers, they could make deals.
I disagree (only slightly). The 20s and 30s saw a conflict between much more major nations (Germany was rather powerful, and so were the Western European nations she was attacking). Right now, it's one superpower against two non-power groups (Muslim Extremists and Al Qaeda, neither of which are even in control of any nation or backed by a major populace).
But as the number of participants increases, the more the regional concerns of the smaller nations come to dominate over global concerns. Plus, the more nations that are involved, the more likely one of them is to be a cheater.
True, that is becoming apparent right now.
There is an old saying that, although I cannot remember where or when I heard it, went something like: "War is only illegal if you lose." I guess what I'm trying to get across is that we are not at war with any spacefaring nation, so any attempt at "breaking" the "space laws" would be much more noticeable and frowned upon, and potentially acted upon.