It was a festive atmosphere on Saturday when the Rafah crossing point between the Gaza Strip and Egypt was re-opened by Egyptian authorities after being closed for 4 years. The blockade had been imposed by Israel in response to the Hamas take-over of the Gaza Strip in order to prevent weapons and terrorists from entering the area. Egyptian cooperation under ousted President Hosni Mubarak was a sore point in relations with the Palestinians and with the Arab world, but American administrations agreed that an open border was dangerous. Notwithstanding many human interest stories relating to individuals crossing into Egypt on Saturday, the Israelis fear that the new situation will make it impossible to stem the flow of sophisticated weapons to Hamas which managed to find their way into Hamas hands even during the blockade. A larger question the re-opening begs is whether security cooperation between Israel and Egypt will survive Mubarak’s demise. Since his ouster, there has been frequent talk of challenging the historic 1979 peace treaty between Israel and Egypt; and Islamist groups are rapidly gaining in strength.