“Although . . . polls have often concluded that most Palestinians, at least in the West Bank and Gaza, support a two-state settlement, they have also shown that there is almost complete unanimity among Palestinians in support of the “right of return,” the implementation of which would necessarily subvert any two-state settlement. And Palestinian Arabs are equally unanimous in denying the legitimacy of Zionism and Israel—which, again, would raise a vast question mark over the durability of any two-state arrangement.”