xtisme* and Malthus,
Most of the post-WWII states have broken up by civil war or the end of colonialism (Koreas, Vietnam for a period, Former Soviet States, Former Yugoslavia, Czechs, East Timor, Eritrea, etc.). These are different in kind from states created by outside powers from whole cloth. Almost all of them follow our traditional notions of self-determination–in both the legal and political sense. We might fairly put Taiwan in that category, though I think there are some other important differences. The point of the Taiwan example was merely that people do question the legitimacy of other states, so we can put aside whether it is fairly analogous to Israel in all respects.
As Malthus points out, unlike the majority of post-WWII states, most of the Middle East nations were essentially created by foreign powers. At least two things distinguish them from Israel. First, Malthus is simply incorrect about geopolitical relevance; geopolitics isn’t limited to conflict over resources (though that a poster called Malthus would be making that argument is amusing to note). It is also, of course, about spatial, social, and cultural conflict. Israel, a Jewish Democracy, placed in the heart of the Middle East, has since its founding been at the center of regional and world geopolitics. This is arguably a little circular, since questions about Israel’s legitimacy are part of what lead to the conflict that puts it there, but not entirely circular because of the above-mentioned obvious factors. You’ll note that when Iraq’s existence became a central issue because of the US war there, there was a lot of talk about the legitimacy of Iraq as a coherent nation and discussion of breaking the state up into other parts.
Second, drawing new formal borders while leaving the traditional demographics and power structures (as in Jordan, for example), is quite different from an intentional movement to transplant millions of people to a new area for the purpose of creating a new state. The creation of Jordan is just fundamentally different from the creation of Israel in the broad view; both involve foreign powers drawing lines, but there is more to the creation of a state than new borders.
Malthus argues that Israel is singled out because people are questioning the legitimacy of Israelis, as opposed to just Israel. That may be so. Part of what makes Israel unique is that a people were transplanted there. That makes it unique and raises unique questions about its legitimacy. But that doesn’t make it unique and questioned because those people are Jews. It would be the same if they were some other diaspora (Roma, say).
The bottom line is that Israel does have a unique history. It was created as a refuge for a diaspora persecuted because they did not have their own nation. That act of creation is different from giving borders and a new name to an existing ethnic-state. To be clear, while I think these differences fairly cause people to wonder about Israel’s legitimacy, I don’t think these differences suggest that Israel is illegitimate. Far from it. I would think that these some of these differences actually cut in the opposite direction, making it more legitimate than, say, Taiwan.
*–I realize your position is more moderate, but I found it useful to group the arguments.