As the government and IDF now admit, nearly all terrorists and potential terrorists are caught at road blocks, checkpoints, and initiated preventative raids. Intelligence stops most terrorists, not walls and fences. Moreover, as Hamas in Gaza and Hezbollah in Lebanon showed, walls cannot stop rockets and missiles. The “separation barrier” has little or no security purpose; it was intended to mark what Israel would like to keep, and what it is willing to concede to a Palestinian state.
Quantum theory of peace – Israel Opinion, Ynetnews