As diplomats scramble to piece together the parts of the Middle East peace meeting that the United States is determined to convene in November, one crucial question is getting too little attention: How will success be measured?

President George W. Bush offered little guidance on this issue when he announced the idea of an international meeting during a speech on July 16. Bush said the conference will "review progress" on Palestinian institution-building, "look for innovative and effective ways to support further reform," and "provide diplomatic support" for bilateral talks between Israelis and Palestinians. These general goals will not suffice.

From the outset the president created obstacles even to convening the meeting by saying participants must "support a two-state solution, reject violence, recognize Israel's right to exist, and commit to all previous agreements between the parties." While these conditions for participation appear reasonable, they in fact will act as a barrier to the participation of the parties most critical for the meeting's success. Syria does not meet these criteria, and Saudi Arabia is unlikely to attend if Syria is not invited.

The president wants to exclude Syria for reasons associated with Syria's abysmal behavior in Iraq and Lebanon. But doing so could scuttle the meeting itself.

Even if the meeting does take place, without far-reaching goals, Bush runs the risk of convening a meeting that opens the door to an empty room. Previous Middle East conferences have risen or fallen on this question, and thus it is important to assess what an international meeting at this time could achieve in the Arab-Israeli peace process. Four outcomes could very well determine success.

First, the meeting needs to articulate the goal of the peace process and the process for reaching that goal. The goal is to reach an end of the Arab-Israeli conflict. There is no longer any rationale for attempting partial or interim solutions, which in the past were supposed to build trust but which actually eroded trust and confidence. The process by which to attain this goal is serious, sustained negotiations - bilateral, but accompanied by close and active U.S. involvement.

Second, the meeting needs to take a stance on the most critical behavioral issues in the conflict. Palestinians must leave the meeting committed to zero-tolerance on terrorism. They must also commit to building the institutions of statehood as a prerequisite to achieving statehood. And Israelis must leave the meeting committed to zero settlement activity. They must also commit to fundamental change in current restrictions on Palestinian movement in the West Bank. The meeting must also produce a system to monitor these activities, and hold the parties involved accountable for their actions.

Third, the meeting must yield agreement on the principles that will inform the bilateral negotiations on final status. Prime Minister Ehud Olmert of Israel and Mahmoud Abbas, president of the Palestinian Authority, already are engaged in deep discussions of such principles, and it is not the proper role of the meeting to pre-empt those direct talks. However, the United States must insist that the two sides reach agreement on the principles or terms of reference for negotiations in advance of the meeting, so that there will be a pathway forward to serious negotiations. These principles must address the core issues of territory, security, refugees and Jerusalem.

Finally, the meeting must establish a realistic timetable for negotiations and milestones for measuring whether the parties are moving toward meeting the timetable. Deadlines in the Middle East and elsewhere have the habit of being missed, but they at least produce a concentration of the key collective minds as the critical dates approach. The absence of deadlines and timetables will surely be taken as a signal that the process is not serious.

The alternative to aiming for these outcomes is a failed meeting. There is no benefit - and great danger - in convening a meeting with limited goals and no follow-up. Enemies of peace, especially Hamas and Iran, are waiting to exploit failure; a meeting that provides the illusion of progress but lacks substance will be welcomes news to them. Thus, it behooves the Bush administration to set the bar high for this meeting and to establish serious goals that ensure success.