Steven Den Beste says that the the "roadmap" between Israel and Palestine is a way for Sharon to buy time. This is the only plausible explanation I can think of for Sharon signing off on the plan. It’s clear that the current Palestinian leadership (meaning Arafat) benefits from terrorism in terms of funding and popularity. Even if Abbas was set on real reform, he would be unable to keep Hamas, Hizb’Allah, or the al-Aqsa Martyr’s Brigades in check. It is entirely clear that the current situation between Israel and the Palestinians is not condusive to peace and is unlikely to be so in the immediate future.
Rumor has it that Sharon’s ultimate strategy is to wait. The Palestinians are dependent on shipments of arms and aid from Saudi Arabia, Syria, and Iran. Their support from Iraq has now effectively ended, and all three of the other main supporters of the Palestinians are facing great political pressure to end their support of militant groups. If the sources of arms and funding dry up, the intifada cannot continue.
Sharon knows that the political climate favors Israel. The war on terrorism is starting to take pressure off Israel and onto terrorist-supporting nations. It seems as though he knows that the "roadmap" is a futile gesture, but it shows that Israel is committed to the idea of a two-state solution, which is the only way of stabliizing this conflict over the long term. The "roadmap" will not be carried out without the Palestinians finally ending terrorism, and Israel will not have to make large concessions until that step is reached. In the end, it is the same old stalemate, except the militants no longer have time on their side.