Having spent the better part of two decades traveling the negotiator's highway, I've often thought about why some deals get made along the way and others don't. Granted, I've labored almost exclusively in the Middle East coal mines -- an often bizarre, idiosyncratic, and exceptionally dysfunctional place where deals rarely, if ever, get done.

But paradoxically, failure can be instructive about the factors required for successful diplomacy. And clearly the Middle East offers up a pretty good testing ground for what hasn't worked. Indeed, with so many canaries dying in those mines over the years, you'd think we'd have figured out by now how to keep them alive.

Every conflict in the world is unique, and there's always a risk in overgeneralizing. But I think there are a number of core verities about how deals get done that transcend the politics, culture, and history of any particular dispute.

Let me apologize in advance to any number of graduate programs in conflict resolution, peace studies, and negotiation theory to which students (and their parents) contribute millions of tuition dollars every year in return for questionable high-brow theories expounded by many professors with no experience in either successful or failed negotiations. Save your money.

Here's a low-brow but reliable guide to how and why deals get done. You can apply these principles to just about any negotiation anywhere, about anything that's worth negotiating about.

1. Nobody Ever Washes a Rental Car

So spoke the ever-controversial, provocative, and -- in my book -- brilliant Larry Summers, former president of Harvard University and former U.S. Treasury secretary. One day wandering around Davos, he dropped this bombshell on me. It took me a full hour to figure out what Larry was talking about. But then it hit me. People, including you and me -- not to mention Israelis and Arabs, Irish Catholics and Protestants, Americans and Russians -- care only about what they own.

Without ownership, no negotiation worth anything can succeed, and if by some miracle it does, the agreement reached won't last. The locals in the fray -- whatever the conflict -- need to invest enough in the outcome to make it work. That doesn't mean they need do the deal all by themselves, without outside help. What it does mean is that the deal gets done largely because it's in their vital interests to do it.

I'm not a great believer in the ripeness theory of conflict resolution. Historic disputes aren't like apples or coconuts. They don't just one day fall off trees. A conflict may never be ripe or ready for resolution, but sometimes catalysts -- war, diplomacy -- can shake the tree. When that happens, there has to be enough investment by the locals to survive the ups and downs and inevitable crises that mar any road to the deal.

Every breakthrough in Middle East diplomacy, from the Egypt-Israel peace accord to the 1991 Madrid peace conference, came in response to events that the locals themselves set into motion and that changed their calculations. Indeed, ownership -- that elusive trait that pushes parties to do things they might otherwise not consider -- must be homegrown. It can't be artificially produced in some laboratory or in a would-be peacemaker's bell jar.

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2. Without Pain There's No Deal

Ownership of tough decisions requires leadership. But even strong leaders won't move unless there's urgency. Without the threat of pain or the potential of gain, why would a leader -- even an extraordinary one -- want to risk decisions that could have existential consequences? (See: Egyptian President Anwar Sadat and Israeli Prime Minister Yitzhak Rabin.) They won't and they don't. That's why most successful Middle East diplomatic efforts were initially triggered by war and insurgency -- for example, the October 1973 war, the Gulf War, and the First Intifada.

At the same time, pain alone isn't enough. If it were, the Arab-Israeli conflict and any number of other global traumas would have been resolved long ago. Incentives are necessary too. It's the marriage of the two that makes the deal possible. Sadat traumatized the Israelis by crossing the Suez Canal and inflicting serious losses on their forces, but he was able to offer a historic gesture of reconciliation by visiting Jerusalem four years later. The First Intifada was followed by the Oslo agreements, while the Second Intifada brought plenty of pain but had no diplomatic counterpart.

There's an important caveat here. When one leader or side isn't as compelled as the other to reach a deal, it can be fatal for the negotiation. Israeli Prime Minister Ehud Barak was semi-desperate for a deal at the July 2000 Camp David summit; Arafat wasn't, sensed Barak's panic, and used it to see whether he could reach a better deal.

This isn't just a fact of life in the Middle East. Take a look at the recent crisis over Chinese dissident Chen Guangcheng, who in April fled house arrest to the U.S. Embassy in Beijing, which appears to have negotiated a deal with the Chinese government to allow him to travel to the United States. The Americans wanted a deal quickly and lost leverage as a result. The Chinese, on their home turf, could afford to wait.

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3. Look, It's the Food Processors

That's what the inestimable James Baker, who served as President George H.W. Bush's secretary of state, used to joke when he'd see his team members Dan Kurtzer and me bringing him another proposal or diplomatic fix. Urgency can get things started, but process is critically important to ink the deal.

Process gets a bad name. It's easy to see why. Process can be endless and directionless; it can often hurt rather than help the chances of doing the deal. But when done right, it's essential. Indeed, when you think about it, process is just another way of managing an issue you can't resolve today.

Most conflicts evolved in phases, over time, and are resolved that way as well. It takes time to build trust and test the proposition that negotiations can get both sides what they want. Also, time is required to structure the agreements, particularly when issues of security are involved. The Egyptian-Israeli peace process played out over a period of almost nine years, from the first disengagement agreement in 1973 to Israel's final withdrawal from Sinai in 1982. That process succeeded -- but the Oslo process took about that long too, and it didn't.

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4. Where's the Beef?

That brings us to perhaps the most important and obvious point about when negotiations succeed and fail: Does the negotiation successfully balance the interests of all parties? Does each side believe that it has a reasonable expectation of achieving its core requirements from the beginning?

Because nobody in life gets 100 percent of anything, both sides must adjust their expectations in any negotiation. I hear the Rolling Stones playing in the background. Whatever the real meaning behind their classic song "You Can't Always Get What You Want," they got it right as far as negotiations are concerned: You can't always get what you want -- but if you try sometimes, you just might find you get what you need.

Sadat may have wanted an agreement with the Israelis that would include Palestinian rights -- but all he needed was Sinai to close the deal. The Palestinians and Israelis got neither what they wanted nor what they needed from the Oslo process, in large part because the gaps between them on the core issues weren't bridgeable (and still aren't) and because the incremental nature of the process itself worked against building up the trust required to reach a final deal.

In most situations, each side will affirm that its needs -- in diplospeak, a leader's "core requirements" -- are met by submitting them to two tests. The leader must believe that he or she got the best deal possible; indeed, leaders have to hone these explanations to justify bold, risky action to their domestic constituencies. The second test is the agreement's capacity to stand up to broader public scrutiny. Secret diplomacy may be required to start the process, but the terms of the deal must also measure up to the harsher light of public exposure. Also, it helps greatly if both parties to the accord are not trying to undermine the other by claiming who got the better deal.

There can be no games or funny business here. "Creative ambiguity" can sometimes start a process, but it's fatal when it comes to trying to close one and reach an enduring agreement. The classic example is U.N. Security Council Resolution 242, which was passed after the 1967 Six-Day War and was intended to bring an end to the Arab-Israeli conflict. Egyptians, Israelis, Jordanians, and Syrians all accepted the resolution -- but their differing interpretations of it, particularly on the issue of Israeli withdrawal from territory seized in the 1967 war, prevented it from pushing peace negotiations forward. Negotiations must produce what each side needs, and it must be clear from the beginning that if the negotiating is done in good faith it can achieve that result.

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5. Power Politics Drives Diplomacy

It's ironic that secretaries of state are deemed to be nonpartisan and that American interests are somehow construed to be above the political fray. In so many negotiations regarding conflict zones, it's politics -- how much space and credibility the leader has -- that drives the deal. Henry Kissinger used to quip that Israel had no foreign policy, just domestic politics. And with 30-plus governments since independence, each lasting an average of less than two years, it's easy to see why. Nor are authoritarian regimes immune from the pull of public opinion and feuding elites. And in the case of Arab leaders, regional pressures from other Arab countries can be a compelling factor for action or inaction.

It's absurd to separate diplomacy and deal-making from internal politics. Barak went to Camp David in July 2000 to save his political future; Arafat wouldn't accept what Barak offered because he believed it would be the end of his. Negotiators are also leaders who are accountable to their constituencies -- if they are to transcend the forces in their societies who are opposed to an agreement and bring along those who are on the fence, they need a great deal of help from their negotiating partners and from outside parties ready and able to provide economic, military, financial, and political goodies.

It takes a rare leader to rise above domestic pressure and take bold actions that are in the best interest of their publics. Leaders are prepared to make tough calls, but not suicidal ones. American negotiators too frequently dismiss and trivialize the so-called politics of diplomacy. But no agreement can be reached or endure without a sustainable domestic consensus.

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6. The Proverbial Third Party

If some of the conditions discussed above are present, the mediator has a chance of success. The problem, of course, is that all too often those conditions don't exist. The result -- no matter how much commitment and enthusiasm abound on the part of the third party -- is failure.

The debate will rage on for years about the extent to which an outside party can serve as a catalyst to energize the locals in any dispute. My views on this matter have hardened considerably over the years, at least in the context of the Arab-Israeli conflict, which I know best. After all, failure can be life's great teacher. America has the capacity to affect any situation. But it does not have the capacity to create the will and political courage for parties locked in an existential struggle. The United States has had a difficult time succeeding even when the above factors are present.

In the history of the Arab-Israeli negotiations, there's no precedent for a successful U.S. initiative that wasn't preceded by some bold act of war or diplomacy on the part of the locals. The inconvenient truth is that the old saw -- so despised and ridiculed by peace processors everywhere -- was right all along: The mediator can't want a deal more than the parties themselves.

Don't believe this eternal truth? Think only about this: The only three breakthroughs in the history of Arab-Israeli peacemaking -- involving Israeli deals with the Egyptians, Jordanians, and Palestinians -- came about through secret diplomacy in which Washington wasn't even involved. The negotiators' highway, after all, always traverses somebody else's land. It's a lesson that Bill Clinton, George W. Bush, and Barack Obama have all learned the hard way: If you don't know the real estate, it's easy to get lost along the way.