Egyptian control of the border means rockets come from Iran and elsewhere in order to be launched into Israel, and violence against Israel in the Sinai is promoted in Gaza. If that had been done in Cast Lead, would the present operation in Gaza be requried now? I'm sure the cost benefit analysis has been done and it comes against such an operation, but I don't understand why.
Palestinian youths throw stones at security forces in Shoafat, E. Jerusalem; none injured (Haaretz)
from the article: LIVE BLOG: Day 3 of Israel-Gaza conflict 2012