It is being hailed as a historic breakthrough as President Bush and Soviet President Mikhail Gorbachev open a Middle East peace conference Wednesday in Madrid that brings Israel, its Arab neighbors and the Palestinians face to face for the first time in 43 years.

But don't expect to hear anything new. It would be downright astonishing if they said anything different from what the Arabs and Israelis have been saying for years - in the case of the Arabs since the 1967 war, and in the case of Israel since the extremist Likud Party came to power in 1977.Although the meeting around the same table will be a major accomplishment, whether it actually becomes a historic breakthrough will only be determined later, probably much later, in the direct talks scheduled to follow. Only then will real negotiations begin with the possibility of give and take.

On Wednesday and Thursday, Syria, Jordan, the Palestinians, Lebanon and Egypt will insist that Israel withdraw to its borders before 1967, when in a "pre-emptive" attack it overran East Jerusalem and the West Bank, then administered by Jordan; the Syrian Golan Heights; and the Egyptian Sinai Peninsula and Gaza Strip.

The bargaining, if there is any, will be in stage two when the conference is supposed to break down into three sets of bilateral talks - between Israel and Syria, between Israel and Lebanon and, most complicated of all, between Israel and a Jordanian delegation that will include the Palestinians.

The stage two bilateral talks are supposed to begin next weekend, four days after the first conference session ends, but exactly where and when has yet to be announced.

In stage three, which is still mythical, all the countries are supposed to begin talking about such wider issues as arms control and water. But Syria, for one, has refused to have anything to do with them until there is some progress on the other issues.

Left to themselves, Israel and the Arabs wouldn't be sitting down together at all this week. The conference is an American creation, fashioned and forced on the participants after the gulf war in an attempt to prove that the Bush administration, far from applying double standards, is serious about solving the Israeli-Arab dispute that underlies everything else in the area.

Israel goes to Madrid because it has been forced to. More than peace, Shamir wants the land Israel occupies. But for the first time since the Eisenhower administration, the United States is beginning to show its teeth to Israel.

Syria goes because it lost its big-power patron with the end of the Cold War and breakup of the Soviet Union. If President Hafez Assad could get back the Golan Heights, fine, but he also sees the chance of winning over the United States if Israel can be blamed for the failure of the conference.

The Palestinians attend on humiliating terms because they are desperate, desperate enough to brush aside the radicals who threatened the delegates and mainline PLO leaders with death for agreeing to go. Nothing else seems likely to save even part of the homeland they have lost in several wars. Terrorism backfired in the '60s, they again chose the wrong side in the gulf war, and the infitada uprising has petered out.

Jordan goes for its own survival, threatened as long as the Israeli-Palestinian dispute continues. Lebanon needs to get the Israelis out and eventually the Syrians as well.

Having made its own peace with Israel, Egypt would like to end its isolation. Saudi Arabia and Morocco look on nervously as observers, ready to follow the crowd.

That the conference meets at all on Wednesday will be a big step forward. But seldom will a conference have met with so many hang-ups and fewer prospects.