The upheaval in Egypt demonstrates the folly of those who claim to support Israel yet who seek to compel Israel to withdraw to the pre-1967 borders without adjustment.
The pre-1967 borders are what amounts to the completely arbitrary armistice lines drawn at the end of fighting when Arab armies tried to destroy the newly declared State of Israel.
As described in The Palestinians: Who Are The Real Peace Partners? (h/t Carl in Jerusalem), the negative reaction of Palestinians to revelations that Palestinian Authority leaders considered a territorial compromise with Israel demonstrates that Israel may have peace partners in some Arab leaders, but it does not have peace partners in Arab populations.
There is no legitimate analogy of withdrawal to the pre-1967 borders to the Israeli withdrawal from the Sinai after the 1979 peace treaty with Egypt.
As the map of Sinai at right indicates, the Sinai peninsula is enormous, with mountain ranges which serve as natural tank traps. Some of the most monumental tank battles were fought in these mountain passes and flat deserts when Egypt invaded in 1973. The 1079 treaty imposed limits on the quantity and quality of Egyptian troops and weapons in Sinai, so that Israel did not face Egyptian tank divisions near its border.
The depth of the Sinai provided a buffer zone which made peace possible — unless and until an Egyptian government were to breach the treaty. With the possible collapse of the Mubarek government, the buffer zone of the Sinai is even more important.
No such buffer exists in Israel proper.
Contrast the map of Sinai with the map of Israel, in which one can drive across the country in less time than many people in the U.S. drive to work.
For Israel to withdraw to the pre-1967 borders, without retaining strategically important parts of the West Bank and Golan Heights, is a risk Israel cannot take.