THIS SPRING, Al Gore testified before Congress on global warming, which he considers an imminent threat to the survival of the planet. When Sen. James Inhofe began his questioning, he dismissed Gore outright, referring to “peer-reviewed scientists” who are “radically at odds with your claims.”

Gore paused, as if to say three “one-one thousands.” Then he wondered aloud what it would take to connect with someone as skeptical as the Oklahoman. Finally, he suggested that he and Inhofe meet privately for a meal so they could talk about the issue away from the TV cameras.

And Bill Ury smiled.

William Ury is the Harvard Law professor who, with his colleague Roger Fisher, wrote Getting to Yes, the basic text on negotiation at all levels. The principles of Yes have been used to resolve hostage situations, legislative maneuvering, peace negotiations, arms talks, and hundreds of other situations where implacable foes adopted the Groucho Marx line, “No matter what it is or who commenced it, I’m against it.”

The principles of Yes work because they express the ideals that we learned as children but often forget in the heat of argument: Listen to others. Don’t get personal. Try to get something for both sides. Look for a win/win solution. Be concrete, but don’t get rigid. Set objective criteria.

This spring, Ury followed Yes with what he calls a “prequel”—The Power of Positive No, published by Bantam Dell. He already has a prominent disciple for his new book in Gore, who participated in a Ury-hosted retreat that brought together critics and skeptics of global warming. In that retreat, Ury taught both sides to say No better, and Gore applied the techniques in answering Inhofe.

massachusetts has become the capital of negotiation studies. Larry Suskind’s Consensus Building Institute at MIT has trained hundreds of people to make conversation, as opposed to combat, a central feature of politics. Two Red Line stops away, Ury’s Global Negotiation Project, based at Harvard, works to resolve political conflict all over the globe—whether it’s the millennial struggles in the Middle East, the ideological clashes in Hugo Chavez’s Venezuela, or the growing struggle over the environment. And don’t forget the Albert Einstein Institution, the leading source of information about nonviolence as a form of political action, which Gene Sharp runs in his East Boston rowhouse.

But smart negotiation has not played an adequate role in Massachusetts politics. According to Ury, the problem might not be that we have a hard time getting to Yes, but that we don’t know how to get to No first. So we go along with undesirable ideas—like the Big Dig, along with its multibillion-dollar “mitigation” projects, and the convention center in South Boston. Or we avoid taking up good ideas, like the expansion of charter schools or the creation of business improvement districts, because of the shrillness of opponents. The result is an undercurrent of frustration, which occasionally explodes in anger.

What is so hard about saying No? We do it all through our lives, starting in the misnamed “terrible twos.” Ury quotes the financial giant Warren Buffett, who is baffled why so many people have a hard time with the word: “I sit there all day and I look at investment proposals. I say, No, No, No, No, No, No—until I see the one that is exactly what I am looking for. And then I say Yes.”

In The Power of a Positive No, Ury argues that people avoid uttering the two-letter word because they confuse it with total rejection. We have to deal with people even when we disagree, and we don’t want to say something that might hurt future interactions. We also live in a manic age, full of distractions and demands that make it easier to just say yes. As a result, we have become a nation of accommodators and avoiders.

“No may be the most important word in our vocabulary, but it is the most difficult to say well,” Ury writes. “At the heart of the difficulty in saying No is the tension between exercising your power and tending to your relationship.”

Ury outlines a three-stage process of constructive dialogue. In the first stage, we reach inside to find our deepest values—what Ury calls the “Yes!” statement. Being clear on those values helps you move to the next step and say “No” to demands that run counter to them. Finally, the issue moves to a request for both sides to find common ground, which Ury signifies as “Yes?”

The Yes!/No/Yes? process mirrors the structure of storytelling, from Athens to Hollywood. In Act I, the hero develops and affirms his deepest values. In Act II, he confronts a great foe that requires him to fight back. In Act III, the great struggle opens new possibilities for all concerned.

No requires more than rejection, as the experience of city politics shows. Neighborhoods regularly say No to even benign projects —housing, parks, schools, new commercial development—that would alter their neighborhood in any way. The No of NIMBY (“Not In My Back Yard”) can poison community life for years. Ury prefers a No that does more than block a project, one that opens the conversation to new possibilities.

I know a nonprofit developer who struggled for years to build affordable housing on an open lot in the Roslindale section of Boston. Neighbors repeatedly rejected the idea in community meetings and zoning board hearings. The developer’s response was to call the neighbors racist and to vow to fight for the housing until he won.

Ury would instead get the developers and neighbors in a room for a long conversation about what the community needed and what it feared. Very often, a community’s intense rejection of change can be tied to being wronged in the past. When the wrong goes unaddressed—or is denied —the wounds can fester. Ury would try to learn everyone’s deepest desires and fears (their Yes!) and then tell them how they can say No in such a way as to open the discussion to new possibilities. The toughest challenge of negotiation is respecting the other side no matter what.

“A positive No respects rather than rejects, even when you’re saying No to someone you don’t like,” Ury told me. “Everyone has as a birthright of basic respect. The first time I taught this course at Harvard Law School, we were in the midst of the war, and the students said, ‘What about Saddam Hussein? Does he deserve respect?’ and I said yes. Professional hostage negotiators [say] the only way to get through [to hostage-takers] is to treat them with politeness and respect. It’s the key to opening their mind.”

The most important part of a good No might be having a Plan B: an alternate plan to use when the other side won’t accept your answer. More than any other part of a negotiation, having a Plan B can force a stubborn opponent to respond.

Suppose Gov. Mitt Romney had listened to his budget advisors on the plan to rebuild the Greenbush commuter line to the South Shore. The administration had lots of good reasons to kill the $500 million project, adopted as part of the “mitigation” agreement to get the backing of the Conservation Law Foundation for the Big Dig in the waning days of the Dukakis administration. When Romney took over the Corner Office, he could have said No to the project, which will do little to improve transit and reduce auto usage—if he had had a Plan B.

Ury says that a good ‘No’ leads to new possibilities.

Plan B would have addressed real environmental concerns and promoted a smart-growth agenda. What would it look like? Different transit investments? Greater attention to strengthening old urban centers? Modern highway management systems? Better siting of major development projects? Hard to say. The state, in fact, has not had a comprehensive transportation strategy since the 1970s. Lacking a viable Plan B, Romney allowed the Greenbush project to move forward.

Contrast that situation with the politics of No on highway construction back in the early 1970s.

At the time, residents of Boston, Brookline, and Cambridge were agreed on a powerful “Yes!”—the devotion to maintaining the character of neighborhoods such as Roxbury and the South End. So they shouted “No” to Gov. Frank Sargent’s plans to build an extension of Interstate 95 and an inner-belt highway, both cutting through densely populated areas. Sargent boldly accepted the protesters’ “No” and admitted that the projects were a mistake. But instead of simply moving on, he looked to his own “Yes!” and hired an MIT political scientist named Alan Altshuler to develop a comprehensive transportation plan for the Boston area. The resulting blueprint—which became the “Yes?” of the drama—drove policy for a generation, leading to transit improvements (like the new Orange Line and the Red Line extension), highways (improvements to Route 1 and early visions for replacing the Central Artery) and urban design (the Southwest Corridor park).

You could argue that Altshuler’s 18-month planning process did more to revive Boston than any other single event. But it all started with a resounding No.

Charles Euchner, a New Haven writer, was the executive director of the Rappaport Institute for Greater Boston at Harvard University from 2000 to 2004.