"The fundamental fact is that Palestinians are under the military domination of Israel. You can trace the history of this conflict back dozens--or, for that matter, thousands--of years, you can weigh competing historical claims to the land, you can try to figure out who was responsible for the failure of Oslo, but you will eventually arrive at this fact, and this fact should, if you're some kind of liberal, shape your position.
...Yet obviously, if you're a progressive, the fact of Israel's military domination of the Palestinians has to dictate your moral math. It's the responsibility of the occupier to stop occupying. Or if you prefer, people have to the right to live free from military domination. If you're a progressive, a believer in universal human rights and international law, you likely accept these precepts. You should. In demanding self-determination, Palestinians are not relying on archaic or secondary principles. As Edward Said put it:
This Palestinian insistence is no unique, decontextualized aberration; it is fully supported by every international legal and moral covenant known to the modern world." (Emphasis Mine.)
It seems that, like religion, military domination depends on who's doing what to whom, for if it's "Our guy" doing it to them (the Crusades, Iraqi War, Gaza Strip), it's right, but if it's "Their guy" doing it (take your pick), well that's just damn wrong.
Here's the proper perspective: It doesn't matter who does it to whom; it's always--unfailingly--wrong.