"If Israel expels millions of Palestinians and keeps the others as second class citizens it will lose the support of pretty much the entire western world (and much of world Jewry). That is almost certain to happen.
It is also likely that without the American people supporting Israel, the US and Europe will start backing its enemies, especially since they have oil and the US wants to resolve the Iraq problem. It is not hard to imagine Syria and Egypt being rearmed and not constrained from fighting by US influence.
So Israel's enemies become armed. It is very likely that the UN will place sanctions on Israel. Israel might not have to worry about terrorism, but sanctions can have a disastrous effect on an economy. Israelis are increasingly becoming more willing to make yeridah and a bad economy and lots of armed enemies on Israel's borders will not persuade them to stay.
So a number of secular Israelis will probably leave. Since they make up most of Israel's human capital, Israel will lose its only natural resource.
As the society becomes more Chareidi dominated, it'll move in the direction of a theocracy, which will scare off much of the other idealistic secular Zionists.So we'll have a copy of Iran, with no world support, sanctioned, myriad armed enemies with nuclear aspirations on its borders, and its economy in dire straits. How do you think that is going to end?"