As National Guard troops in battle dress marched through downtown streets in the days after the destruction of the World Trade Center, New Yorkers asked one another whether this was the future. Was their wounded city-the symbolic capital of the globalized economy-to be patrolled by rifle-carrying soldiers, much like some besieged third-world capital? President George W. Bush’s address to the nation on September 21 made this possibility even more real when he warned: "We will take defensive measures against terrorism to protect Americans."

In past criminal crises, the federal government has shown a fairly light touch in New York, treating the city and its police department with the respect normally due a sovereign. Indeed, while touring the ruins of the World Trade Center, Bush seemed to defer to Mayor Rudolph Giuliani as guest to host. During the president’s address to Congress, Giuliani was seated to the left of Laura Bush, the highest placement in social terms.

But the days of federal deference to New York may soon be over. A safe America requires a safe New York-no president can permit New York to remain an island. But every increment in security will come at a cost, and the costs will be social and political as well as financial. They will threaten to undermine the city’s very being and sense of itself as freewheeling, entrepreneurial, and invincible. New York had spent the nineties fighting crime and remaking itself into the most desirable city in the world. Or as urban historian Fred Siegel says, "The success of the nineties was pushing fear out of public spaces. That fear has now come back in a new form."

New York’s strategic problem will be safeguarding itself effectively and efficiently-tackling public fear while minimizing inconveniences to routine life. But who is now in charge of New York? And who will make the crucial and potentially damaging security choices-Washington or New York?

No one thinks that the FBI, based in Washington with a staff drawn from around the country, can direct security in New York better than the New York police (NYPD). But the bombing of the Trade Center shows that ensuring New York’s safety cannot be an exclusively local function. The FBI and the NYPD will have to work these matters through-and it probably won’t be pretty.

The NYPD, however, is stronger than it has been in years. In these days of crisis, the police have performed heroically and professionally. They have been on duty round the clock, a reassuring, protective presence. In the first days of the crisis, crime plummeted 34 percent over the same week last year-a tribute to the cops and perhaps to some decency even among criminals.

At least twenty-three police officers are missing in the collapse of the twin towers, most from the elite Emergency Service Unit. All were (presumed) killed while trying to rescue others. The Fire Department lost more than three hundred men. A popular T-shirt shows a police officer and a fire fighter standing beneath the words: The New Twin Towers.

But the security problems that lie ahead will put the NYPD under far more pressure than at any time in history. For the police will have to think through the right balance of security and efficiency in everyday life.

The New York public had already become accustomed to extensive measures deterring the common thug-metal detectors, photo IDs, bag searches, checks of electronic equipment. The screening devices are often primitive and the training of the personnel poor, but routine security checks prevent some crime and perhaps some terrorism in courthouses, museums, libraries, and most large office buildings. The twin towers themselves had a highly sophisticated security system managed by well-trained personnel.

Accustomed as they may be to routine security lines, New Yorkers are far less amenable to what the security trade calls Israeli tactics-traffic-stopping checkpoints, intrusive questioning, random identification checks, intimate searches, and racial profiling. These are ostensibly meant to deter crime. But they are also meant to remind the public often and aggressively of the presence of terrorists in their midst and to get the public to accept the authority of the police and military. In the Israeli system, police and military authority trump all other authority, as issues of safety come to trump all other issues, including economic ones.

Former Police Commissioner Howard Safir actually introduced a few of these tactics to New York, and Commissioner Bernard Kerik has continued them. Traffic-stopping checkpoints ostensibly for drunk driving or seat-belt use were first used in upper Manhattan and minority neighborhoods. After an outcry about racial profiling, Safir expanded the checkpoints to Manhattan neighborhoods below 96th Street. Huge swathes of important streets, like Third Avenue-a main artery on the East Side-would simply be shut down unexpectedly during prime hours, and all cars funneled through a narrow point. Large numbers of uniformed cops stood around as New Yorkers fumed helplessly. The inconvenience accompanying Israeli tactics is deliberate.

The pedestrian-controlling barriers introduced by Giuliani and Safir in 1998 to prevent jaywalking and improve the flow of vehicular traffic also represent an Israeli tactic-a reengineering to encourage people to go only where they are directed and to accustom the public to accepting restrictions on their movements. Defiant New Yorkers were routinely ticketed and forced to appear in court.

Since the Trade Center bombing, most streets with police precincts or fire houses have been closed to traffic, causing enormous disruptions in their neighborhoods. East 66th Street, for example, a major crosstown artery, is shut down at Third Avenue for one block. Crosstown buses must now make their way north to 72nd Street and across two blocks to the once-sacrosanct Park Avenue, where trucks and buses had been forbidden.

The most important question among all these tactics is, however, do they make the city safer? The evidence is not in, in part, because security tactics are almost impossible to evaluate rigorously. Fred Siegel, for one, thinks New York will be fine in the end because the high quality of New York policing will make the city far more secure than other places. London survived the IRA bombings, and Paris the Algerian terrorists, he notes.

Numb in their sadness, New Yorkers will survive the bombing-and will likely revert to old form, questioning every new restriction on their freedom. They have their natural combativeness to help them out, plus a fury against what Bush called the evildoers. The Bronx coat of arms says it all: No cede malis. Don’t give in to evil.