Thers weighs in on the ethnic-cleansing quasi-debate and makes a good point:

What’s really scary here is that, as he says, Israel’s "mission" is confused on its face, has all sorts of contradictory motivations, and history says that when troops go fight under those conditions, no matter how disciplined they are, atrocities happen. These atrocities, which I devoutly wish I’m wrong and don’t happen, are going to be perceived as part of a program of "ethnic cleansing" by Palestinians and most Muslims. (It already kind of is.)

There’s a bottomless outrage in the Arab world for Israel, particularly when it pummels/encloses/blockades/bombs/invades Palestine, so I’m unsure how different in kind it would really be for a belief to take hold among Muslims and Arabs that Israel is engaged in ethnic cleansing. What’s more important is that there be no ethnic cleansing, and given Israel’s repeated and demonstrated resistance to such a thing — the right used to want to push the Palestinians in the West Bank to Jordan in a campaign it labeled "transfer," which indeed would have been ethnic cleansing — it’s rather unlikely that there will be. 

But the more relevant issue, Thers points out, is atrocity, however you want to definite it. Ten thousand Israeli soldiers are about to be surrounded by a million and a half Palestinians in one of the most population-dense parts of the planet. They’re about to be put there amidst a media blackout. That is an unfair burden and a serious test of discipline.

Also, for a sense of how apprehensive Israelis are about the invasion, don’t miss this Washington Post story.