Peace with Egypt, a central pillar of Israel's security for three decades, was badly hurt Thursday. An active war between Israel and Egypt has not broken out yet, but there is hostility, and unhindered acts are taking place from Egypt's sovereign territory.

Prime Minister Benjamin Netanyahu's belligerent threats to punish those who attack Israel do not deter the terror organizations. Those who come to commit suicide are not alarmed by words, especially when uttered by one whose envoy was sent to Cairo to talk with Hamas' military leader in Gaza, who holds Gilad Shalit's fate in his hands.

There is no need for an investigation. The IDF admits it received an advance warning - perhaps about two weeks ago, and more warnings in recent days - about plans to carry out a terror attack similar to those carried out Thursday.

There was no intelligence blunder. It was a mistake in operative evaluation. The Southern Command assessed the cell would enter Israel somewhere along the border between Egyptian positions, not under one of the position's eyes. The IDF expected the cell to try to sneak in at night, not in broad daylight, and to attack a military target in a bid to abduct a soldier.

A similar mistake in April resulted in a civilian bus being attacked with an anti-tank missile near Gaza, killing a teen, while traffic was closed to military vehicles.

There's no comfort in knowing that usually the intelligence and forces are more effective and manage to foil attacks before they are carried out. For terror, being successful in one out of 10 planned attacks is enough.

This is why Israel has no sufficient defensive or deterrent answer. An attack would lead to escalation, to fire on the southern (and central ) communities. In this situation, Israel can only lose.

With the crumbling of Mubarak's government Israel has lost a cold but tough partner. Mubarak also had difficulty imposing authority on Sinai, but his deposers and heirs aren't even trying. As long as Israel held the Gaza-Egypt border, a reasonable modicum of security prevailed along the border between Rafah and Eilat.

Now there is no Egyptian army threatening Eilat, but Hamas, together with "rogue" organizations like the popular resistance committees and Islamic Jihad, Hezbollah, Iran and other terror groups, have created an intolerable situation.

Israel does not border on the Suez Canal or the Nile. Egypt is a hostile state that enables Israel's enemies to attack it. The American-run multinational force is useless. So will NATO forces be if they are sent on peace policing missions.

Without Mubarak, and with Hamas in Gaza, with a Jordanian king fearing for his throne and an American administration that doesn't believe in Israel's judgment, what comes next could be even worse.