THE Madrid conference was a beginning. People who have been separated by a wall of animosity walked through that wall. Their words were often less than cordial - the Syrians and Israelis unleashed some verbal salvos - but all parties want the talks to continue.Most anxious to see the process keep going, perhaps, are the Palestinians. They gained the most from the days in Madrid. The Palestinian negotiators showed themselves adept at stating their case. They were congenial with their Israeli counterparts, in sharp contrast to the Syrians' icy aloofness. The Palestinians were given a tremendous boost at the outset by US Secretary of State James Baker, who insisted they be allowed to make an opening statement equal in length to that of the other parties. But the Palestinians know that the road ahead is tortuous. They've affirmed their readiness to discuss a plan for interim self-rule, or autonomy. Can they and the Israelis arrive at a definition of self-rule that keeps alive their hopes for genuine independence? Camp David negotiators devised a plan in 1980 that called for Palestinian control over key administrative areas, such as justice and agriculture. Palestinians rejected it then. But then they had neither a voice at the talks nor a US commitment to embrace all regional players in a comprehensive peace. They have both now. The politics swirling around the edges of the peace process are alarming. Arab and Islamic extremists have targeted the peace negotiators. Their recent gathering in Tehran was a hate-in for those whose only "solution" to the problems of the Middle East is the destruction of Israel. Extreme elements in Israel are doing what they can to thwart the talks, too. The opening of a new Israeli settlement on the Golan Heights, ballyhooed by Housing Minister Ariel Sharon, makes the hard work of negotiations just that much harder. The immediate hurdle of where to hold coming talks will be cleared. It's yet another procedural point with symbolic weight. A venue close to the Middle East but not in it is a possibility. So is Washington. The international thrust behind the meetings has to be maintained. Mr. Baker has a China trip to prepare for, but he'll have to closely monitor developments in the Middle East regardless. The peace process has revived largely because of Baker's determination to take advantage of changes in the region and bring the process back to life. US urging and goading remain critical.