Just how messed up is Israel?

[Incongruous]

No, the point I was making was that, according to the generally accepted international rules of the time, the mandate was within the purview of the UN to distribute in whatever fashion they thought best. Obviously, this only applies to the original territory from the 1947 agreement. Israel holds suzerainty over any other lands only by right of conquest. Right of conquest was, but is no longer, acknowledged as valid in international law.

Now, you can argue that the UN decision was stupid in that it failed to address the resentment and deep disagreement felt by many (most? all?) Palestinian arabs towards that decision. It's pretty clear that racism was not the force motivating the UN decision, though being that high-handed toward the locals was presumptuous at best. Yet, by the standards of the time, this was viewed as being within the purview of the UN.

I've always wondered how things would have turned out had the CCCP not opted out of the meeting and had chosen to interpose its veto on the whole thing.

No the mandate was no such thing, what occured was a travesty of International justice.
Why even bring up the right of conquest? By the time Israel had been established it was already well past it, the U.S had been very certain about this.

The decison to recognise Israel was a farce, lead by the U.S, it was more than high handed, it was racism, the idea that you should help one ethnic group kill and oust another from its homeland is racist. The Jews were percieved to be more worthy of a home than the Palestinians.
The U.N did what the U.S told it to, deep and critical thought were not part of the process.