If there’s a gold standard for a mayor’s handling of a crisis, it is . . . well, you know what it is. It’s Rudolph Giuliani standing on a sidewalk on September 11, 2001 amid the wreckage of New York’s World Trade Center, reassuring citizens. And if there’s a lead standard for a mayor’s handling of a crisis, it may be Jean Quan’s performance this fall when her Oakland, California police department cleared an Occupy protest site.

Mayor Quan’s public handwringing and contradictory actions were well documented. She ordered police to push protesters out of their camp near city hall, then allowed them to set up the camp again the next day, all the while agonizing over which was the right thing to do. The raid on the camp and the protests that followed resulted in serious injuries to several protesters and television footage that made Oakland look like a war zone. Later, Mayor Quan tried to apologize to protesters and was booed off the speakers’ platform. The police were furious with her equivocations, and so were the protesters. Not surprisingly, a petition drive to recall Quan was launched almost as soon as the tear gas cleared.

We could make a long list of the things Mayor Quan did wrong in this crisis: indecision, incoherence, lack of vision, lack of follow-through—combined with an astonishing inability to read situations or understand how others viewed her. But a better question than what went wrong with Jean Quan is to ask its opposite: What do good leaders do differently in a crisis, people like Rudy Giuliani?

To answer that, we have to look at crises as a special kind of problem. Most leaders, including Mayor Quan, have some notion about solving problems under normal circumstances. What makes crises so different that leaders feel abandoned by their instincts?

Three things: First, they are unexpected. Whether it’s Hurricane Katrina devastating New Orleans or a scandal at city hall, crises seem to come out of nowhere. Second, they appear to threaten the usual ways of doing things. This is why leaders sometimes lose their bearings; they don’t know what—or whom—to trust. Finally, crises are urgent. They fill the news and the conversations of citizens, events move quickly, and leaders must deal with them NOW. The pressure can be enormous.

When you put these things together—surprises that challenge the status quo and demand immediate action—you see how crises can paralyze leaders like Mayor Quan. But they don’t have to; they can just as easily make you a hero. Rudy Giuliani started the day on September 11 as a deeply unpopular mayor whose pettiness and bullying ways had worn out his welcome with New Yorkers. He ended it as “America’s mayor,” as many news articles called him, and the change in his image was solely the result of how he handled a major crisis while the whole world was watching.

Let’s take the elements of a crisis, then, and see if we can find a formula for success . . . or, at least, survival.

Crises are surprises. This means they aren’t on your agenda, and, therefore, can’t be planned for. Nobody runs for mayor to deal with a hurricane, a terrorist attack, or protesters camping out at city hall. (For that matter, nobody wants to be city manager so she can deal with a bridge collapse or a nonprofit executive so he can manage a financial scandal.) But if you can’t plan for crises, you can at least prepare for them.

What’s the difference? Planning is about steps (I’ll do this, then this, then that . . . over a known time period). Preparation is about contingencies (if this happens, I’ll do that . . . if I ever need to). There’s an element of planning in thinking about crises, but planning takes you only so far because these events are . . . well, unexpected, urgent happenings that appear to scramble the usual ways of doing things.

What you can do in preparing for a crisis is think through a few steps and then concentrate on roles and responsibilities. For instance, if a natural disaster were to strike, what would be the most important tasks the city government would have to undertake? What decisions would have to be made? Who would be needed to make these decisions and execute those tasks? How should these people work together, and where should they be? What resources would they need?

You can construct scenarios for all kinds of crises—public safety emergencies, human disasters (say, a gas-main explosion or contaminated water supply), even political crises (a scandal, for instance). You can’t be very specific—not all hurricanes, gas-main explosions, or scandals are alike—but you can at least know where everyone in the decision team should meet and have a checklist of general things they should do (get the facts, assemble background information, brief other leaders, contact the news media, etc.). And you can prepare yourself and your emergency team for the what-ifs.

This was why Rudy Giuliani was so calm on September 11. He had already been there . . . in his mind. As he writes in his 2002 memoir, “Leadership”: “Throughout my time as mayor, we conducted tabletop exercises designed to rehearse our response to a wide variety of contingencies. We’d blueprint what each person in each agency would do if the city faced, say, a chemical attack or a biomedical attack.” This wasn’t just for the police and fire departments, he adds; it was for him and his staff as well. “The goal was to build a rational construct for myself, and for the people around me. I wanted them ready to make decisions when they couldn’t check with me. The more planning we did, the more we could be ready for surprises.”

Again, this isn’t planning in the conventional sense. It’s more like role playing, so everyone involved will know his role if the worst happens and, therefore, not be paralyzed.

Crises challenge the status quo. Take a deep breath. Crises rarely change things at a fundamental level, especially in environments as complex as cities. But they often appear to. A riot, for instance, can suggest to people that public order and the old ways of decision making have broken down and cannot be restored. And doubt can feed on itself. After Katrina, some believed New Orleans would never recover, which slowed the city’s recovery. The same thing with New York after September 11.

Because crises often create periods of doubt and genuine uncertainty, leaders must do two things immediately. First, they must do everything in their power to restore public order. Second, they should promise an open-minded look at how the crisis came about and what it means for the future. This is important. Good leaders don’t promise that everything will return to the way it was. (There’s always at least a possibility that things really can’t be as they were.) But leaders can promise to examine carefully whether mistakes were made that caused or exacerbated the crisis and, if so, fix them.

Think of it as dealing with a car wreck. First you take the victims to the emergency room to stop the bleeding and set bones. Then you do the accident inquiry. Chances are, once the crisis has passed, you’ll find that major changes aren’t needed. But in the heat of the moment, people don’t want to hear that everything is fine because things don’t look fine. They want assurances that someone will take a long and fair look at why happened and why.

Consider how differently things would have turned out for Mayor Quan if she had followed this path in Oakland. First, she could have spelled out before the police action and after why the city had to clear the camp (for health, public safety, economic reasons, etc.). She could have been resolute about not allowing the conditions to be repeated (that is to say, no future camps). Then she could have promised an open-minded examination of how peaceful protests could be accommodated in the days ahead that would achieve what the Occupy activists wanted without repeating the problems the city was concerned about. Firmness in the short term . . . with an open mind for the long.

But what about those instances where a crisis exposes a situation where things can’t remain the same? A riot, for instance, like the one Detroit experienced in 1967 that came as the city was experiencing a major demographic transition (and which hastened the transition)? Or, say, the closing of a major economic institution at a time when the city’s entire economy is shaky? In these instances, it’s even more important to deal with the crisis on a short-term, long-term basis: short term to restore order, obtain temporary aid, and so on; long term to find lasting answers, which might include a whole new way of doing things.

Crises are urgent. In some crises, leaders don’t have a week to seek advice from others. They may not even have a day. On September 11, Rudy Giuliani had minutes to size up the situation and act. But the smartest leaders always ask first about the timeline. If they have a day, then they take the entire day to make decisions. If they have an hour, they take the full hour.

Why? Because decisions are almost always improved by more information and different viewpoints. This isn’t indecisiveness. It’s intelligent decision making. It’s based on the belief that better answers emerge as informed people debate the right course in constructive ways.

The best example and one of the most studied presidential decisions of all time was the 1962 Cuban missile crisis. The stakes could not have been higher. Almost everyone involved saw that the crisis might end in war, perhaps nuclear war. And yet the only options presented to President Kennedy at first were to do nothing or launch a secret, preemptive air strike that would have almost required the Soviet Union to retaliate in some way.

President Kennedy insisted that his advisors take the few days they had to look for other answers and debate the alternatives among themselves. And it was from this debate that a third alternative came about: a “quarantine” around Cuba (they didn’t want to call it a blockade for fear of provoking the Soviets). As you know, this unexpected third way worked, and the crisis ended better than anyone could have imagined (missiles were gone, war was averted, and relations with the Soviet Union even took a turn for the better). And it came about because Kennedy knew exactly how much time he had to decide and used that time wisely.

But know this: When the time expires, you must act. If you do so intelligently (like Kennedy) and calmly and decisively (like Giuliani), a crisis can be your finest hour. But wilt under pressure, equivocate, and blame others, and it will be your worst nightmare. Just ask Mayor Quan.