Little Green Footballs has this article in the JPost. The money quote from the JPost article is this:
The US administration prepared a list of sanctions it would impose against Israel if Israel refuses to implement the 'road map'.
US officials said the sanctions list includes a reevaluation of Israel's use of US-made weapons in the Palestnian [sic] territories, and the withholding of emergency aid, reported Army Radio.
Now, since Israel is vastly more powerful than the Palestinians, it is reasonable for you to believe that it's worth the cost for the small chance of real peace. But consider, what happens if there comes a demand upon you which would be considered by every Arab to be a capitulation; like, say, removing your security forces from the Palestinian areas? Since it is only through this presence that you've been able to keep the violence from escalating out of control, removing the troops would almost certainly lead to an immediate killing spree.
This demand actually comes fairly early in the "roadmap" process, and is only predicated on the Palestinians stopping the attacks within Israel proper (not within the Gaza Strip or West Bank). Given that the history of "the peace process" has been that if the Palestinians agree to something, they are given credit for it even when they are clearly not living up to their agreements, you as an Israeli leader might think that it is likely that pressure will be brought to bear on you to remove your best protection against Palestinian attacks even while the Palestinians are still attacking you.
In that case, would you refuse to pull back your security, knowing that it would cause the US to impose sanctions against you, or would you withdraw, knowing that you were thus condemning dozens or (more likely) hundreds of Israeli men, women and children to a grisly death? For myself, I know I would keep my security in place, because as an Israeli leader, I would not allow my people to be once more led to the charnel house. If the US actually imposes sanctions in such a case, it is clear that Israel will become weaker over time. The US can impose real restrictions and costs on Israel, and these costs and restrictions would surely weaken Israel at the same time that the Palestinians would be growing stronger, due to the inevitable influx of cash and weaponry that happens every time the "peace process" seems to be making headway.
Now, again assuming you are the Israeli leader in such a situation, do you allow your country to grow weaker while your mortal enemy grows stronger, or do you take action? The reality is, the Israelis are incredibly moral people, and they would almost certainly take a substantial increase in civilian casualties before they would do anything drastic. But eventually, if Israel were to continue both to weaken and to suffer more losses, the time would come to make The Choice: it's us or it's them. This would have to be done before the balance of power shifted too far, and before any external power began to station "peacekeepers" on the ground, or Israel would be unable to take such action without risking its own destruction from its neighbors or from outside forces committed to the "peace process" at any cost.
When the time comes to make The Choice, no human would ever willingly watch his people destroyed, shattered, driven out into a hostile world. Where would the Israelis go, if forced to leave? There is no other place where they would actually be welcomed - not even in the US (not by the millions). At that point, I would rather be anything than a Palestinian, because the might of Israel loosed in such a small area against a lightly armed population would be Old Testament Biblical in nature.
And the blood would not be on Israel's hands, but on America's.