WASHINGTON -- The road to a Middle East peace settlement, ending decades of war between nations, generations of tensions between peoples and millennia of conflict between religions, is full of potholes, despite this week's signing of an Israeli-Jordanian non-belligerency agreement.


The stunning breakthroughs over the last year -- beginning with the Palestinian-Israeli declaration of last September -- look easy in comparison to what lies ahead.


The next six to 12 months will be critical in what is likely to be a process of three to five years, American, Israeli and Arab officials agree.


"If everything goes according to schedule over the next year, then you'll see expanded autonomy for the Palestinians in the West Bank, a peace treaty with Jordan and a breakthrough with Syria" that includes senior officials negotiating a full peace, said Ehud Sprinzak, a political scientist at Hebrew University in Jerusalem.


"The worst case," Sprinzak added, "would be lots of distractions, violence and assassinations. The Palestinians could be in trouble because they don't have a good administration or enough money to make Gaza and Jericho work. Israeli settlers could become more militant. The Syrian track could stall. And fighting along the Lebanon border could get hotter."


The overall goal is to maintain the momentum as the various efforts between Israel and its immediate neighbors are woven together into a tapestry that will not easily unravel.


Peace prospects nation by nation:


?Jordan -- After the signing of the non-belligerency agreement with Israel here Monday, the outlook for a full-fledged peace treaty appears promising.


?Palestinians -- After the famous handshake 10 months ago between Rabin and Palestine Liberation Organization chairman Yasser Arafat, the Israelis and Palestinians must still work out daunting issues. Among them: terms for expanding Palestinian autonomy into the West Bank; redeploying Israeli forces from Arab towns and Jewish settlements; and determining the timing and terms of elections.


"In less than a year, we went from almost zero contacts," said Nabil Shaath, planning minister of the Palestinian Authority in Gaza and Jericho "to negotiations that are continual.


?Syria -- This remains the biggest prize but also the biggest problem in the peace process and the most controversial step for Israel. All issues -- notably how much peace for how much land and over what time -- remain unsettled.


The most optimistic American scenario envisions U.S. shuttle diplomacy resulting in a breakthrough with Syria over the next six months, with a peace treaty sometime next year.


Yet Israeli support for returning the Golan Heights, which Israel captured from Syria in the 1967 Middle East War, does not exceed 5 percent, according to a recent survey. Support for limited or partial withdrawal has risen from 35 percent to 45 percent in the past year but the only deal Syrian President Hafez Assad says he will accept is total withdrawal.


?Lebanon -- Peace efforts have become largely a function of progress with Syria, which has a 40,000-man garrison in Lebanon.


Because Lebanon is Israel's most volatile neighbor, Israel wants a treaty that includes an end to attacks by Hizbollah and other extremist groups -- six months after which it will withdraw from the southern Lebanese enclave it has dominated since the late 1970s.


The fragile state of Lebanon's government after a 15-year civil war will make enforcement of any agreement difficult.


Over the past three months, Israel and most other Arab states have made quiet but substantive progress in negotiations on regional issues. Negotiators are now preparing a study to identify projects to address the principal threats to peace: regional arms proliferation, radical groups, rapid population growth and socio-economic instability.


"There is now a large amount of rationality and order and organization to solving the Arab-Israeli conflict" involving regional nations and international organizations, said a U.S. official.


"This makes it very difficult" for the process "to come undone."