Early in 1982, then-Israeli Defense Minister Ariel Sharon tasked the Israel Defense Forces’ special Devil’s Advocate intelligence branch to do an intelligence estimate for him and Prime Minister Menachem Begin. The Devil’s Advocate, a unique unit that does sensitive out-of-the box analysis only, was asked how Egypt would react if Israel invaded its northern neighbor Lebanon to destroy Yasir Arafat’s Palestine Liberation Organization and install a Christian warlord as the new ruler of Lebanon.

The Devil’s team concluded that Egypt’s new ruler, Hosni Mubarak, who had just come to power in a hail of bullets as his predecessor Anwar Sadat was assassinated on October 6, 1981, would do little or nothing. The IDF knew Mubarak well. He had been trained as a bomber pilot in Russia and risen to command of the Egyptian Air Force before the 1973 October war. His manner was always cautious and conservative; he preferred stability to change. He never sent the Air Force to do bold and risky missions. The IDF estimate said he would at most withdraw the Egyptian ambassador to Tel Aviv in protest but not break diplomatic ties and certainly not tear up the peace treaty Sadat had signed with Begin only a couple of years before.

As a footnote, the Devil’s team said Sadat would have been far more unpredictable and prone to drastic action. He would have been terribly humiliated by an Israeli invasion of Lebanon. But he was gone and Mubarak would be quiet. Sharon invaded Lebanon that summer. Mubarak whined but did nothing.

For 30 years, decision makers in Jerusalem, Washington, Amman and other capitals have counted on Mubarak to bring stability and predictability to Egypt. The Devil’s Advocate judgment has passed the test of time well. After 30 years of tumult in Egypt, first under Gamal Abdel Nasser and then Anwar Sadat, Cairo became a known quantity. Egypt would keep its peace with Israel, albeit cold as ice, and its alliance with America. It might be critical of Israeli or American policies, even harsh in private, but not shake its alliances. Mubarak would be careful, even plodding, never a risk-taker.

Now that is over. Egypt is back in the game. Even if Mubarak or his new Vice President Omar Suleiman, the longtime spymaster of Egypt, survive in power somehow, the old predictability of Egypt’s position in the region is gone. If Mubarak and Suleiman are swept from power and a new more representative government is established that includes members of the opposition including the Muslim Brotherhood, it will be even more of a sea change in the regional geopolitics.

Mubarak has relied for decades on his secret police chief, Suleiman, 74, to keep order and maintain control. Suleiman is a ruthless counterterrorist fighter well known in Western capitals and highly respected by intelligence services around the world. He has often been Mubarak’s go-to political operative handling delicate negotiations—such as dealing with Hamas in Gaza. Mubarak credits him (rightly) with saving his life in Ethiopia in 1995 when Islamic Jihad almost killed him; Suleiman had insisted on taking a heavily armored car, which saved Mubarak.

At best he may be an interim figure for a transition to a different Egypt, however, as the genie is out of the box in Egypt now. History has moved beyond Mubarak even if he tries to resist it.

A more representative government drawn from the diversity of Egypt’s political opposition will be much more inclined to criticize American and Israeli policies. The Egyptian street may accept the strategic logic of peace with Israel and alliance with America, but it bristles at the humiliation of being a de facto silent partner in the siege of Gaza, Israel’s wars against Hamas and Hezbollah and America’s wars in Iraq and Afghanistan (which rely on transit via the Suez canal and Egyptian airspace).

No conceivable Egyptian government will lightly rip up the peace treaty Sadat signed with Begin. The memory of the costs, both human and material, of Egypt’s four wars with Israel remains vivid for Egyptians. But in the event of another Israeli war against Hamas in Gaza or Hezbollah in Lebanon — both very possible scenarios—a more democratic Egyptian government will have to listen to the voices of the street, both the left and the Muslim Brotherhood.

Diplomatic ties could be broken, trade suspended and demands raised for renegotiating parts of the treaty like the demilitarization of the Sinai Peninsula. A new question mark will be raised about the cost of military options in the prime minister’s office in Jerusalem in place of the certitude of the last three decades.

Similarly no Egyptian government will want to cut ties with America lightly. American assistance runs close to $2 billion a year, Egypt’s army is equipped with American gear (including the tanks and the tear gas used this weekend). But democracies have to pay attention to their people. Mubarak could criticize George Bush’s Iraq War and still allow the U.S. Navy and Air Force to use the canal and Cairo west airport to supply it. That may no longer be the case.

Egypt can also be much more active in international forums in criticizing Israeli and American actions. Mubarak’s government pressed hard for the world to condemn Israel’s nuclear weapons program with little success. Mohamed ElBaradei, a former International Atomic Energy Agency chief and Nobel Peace prize winner, will almost certainly redouble the effort to put the Israeli arsenal on the agenda of the U.N. Security Council.

A new Egypt will still be the enemy of al Qaeda and a rival to Persian Shia Iran. It will still want Western tourists and investment and it will behave as a responsible member of the world community. The army will be a voice of caution still. But it won’t be your father’s Egypt any more. In every capital around the world and especially in the Middle East it will be a new game, more unpredictable than just a week ago.