The following op-ed by Professor Alan Dershowitz, Terrorism: Confusing cause, effect, was published in The Boston Globe on January 16, 2006.

Whatever anyone might think of the artistic merits of Steven Spielberg’s new film ”Munich,” no one should expect an accurate portrayal of historical events. ”Munich” portrays a squad of Mossad agents, led by a fictional character named Avner Kauffman, tracking down and killing the Black September terrorists who had perpetrated the massacre of Israeli athletes at the 1972 Olympics. As the movie progresses, Avner becomes increasingly disillusioned with his mission.

His chief concern is that counterterrorism only incites more terrorism, which in turn provokes reprisals. The last shot in the movie rests on the World Trade Center, suggesting a connection between the Middle East’s ”cycle of violence” and the Sept. 11 attacks.

Deepak Chopra wrote that the movie ”draws a trail that leads directly to the attacks of 9/11.”

The trouble with this ”cycle of violence” perspective is that it confuses cause and effect. The period immediately preceding Munich was plagued by airline terrorism, including the blowing up of a Swiss airliner that killed all 47 passengers and crew, and dozens of deadly hijackings. Palestinian hijackings were successful because even when the hijackers were captured, they were quickly released as soon as Palestinian terrorists hijacked another airplane.

This long pattern of high-publicity, low-risk hijackings is what encouraged Black September to up the ante by infiltrating the Olympic Village in Munich.

As I wrote in my book ”Why Terrorism Works,” ”Based on the reaction to international terrorism over the previous four years, the terrorists planning the Munich operation could expect to succeed in attracting the world’s attention and be relatively certain that if any of the terrorists were captured, they would not be held for long.”

In short: Terrorism works because it is successful, and success begets repetition.

In the final scene of the movie, Avner asks his Mossad handler why Israel killed the Black September terrorists instead of arresting them. The answer, never given in the film, is that the arrest method had failed. Arrested terrorists were never tried and imprisoned for long. Between 1968 and 1975, 204 terrorists were arrested outside of the Middle East. By the close of 1975, only three were still in prison. George Habash, leader of the Popular Front for the Liberation of Palestine (a Marxist terrorist group responsible for some of the Palestinians’ most brutal mass killing), noted that Europe’s refusal to imprison terrorists meant that, when it came to plotting hijackings and bombing, ”success [was] 100 percent assured.”

Take the example of PFLP hijacker Leila Khaled. In 1969, Khaled hijacked a TWA plane. She was arrested but soon released. Only a year later, in September 1970, she led another hijacking operation, this time on an El Al flight to New York. Khaled was held in a British prison where, by her own account, she was treated ”as if I were an official state guest.” The British released her — after her second hijacking! — before she had spent even one month in jail.

Both Israel and America pressured the British to extradite Khaled to Israel to stand trial. England refused, aligning itself with every other European country that had refused to extradite terrorists for trial in Israel.

And it is not only Israel whose extradition requests have been utterly frustrated. In 1985, for example, Italy allowed Achille Lauro mastermind hijacker Abu Abbas to flee safely to Tunisia, rather than sending him to the United States to face charges of killing American tourist Leon Klinghoffer.

The best evidence of why the arrest method advocated by ”Munich” would not work was provided by Black September’s own demands in Munich — that Israel free more than 200 imprisoned terrorists. Israel understood that releasing terrorists would encourage future terrorism. Without European cooperation, Israel stood little chance of curbing international terrorism. Sure enough, Germany released the surviving Black September terrorists less than two months after Munich, when Palestinian terrorists ”hijacked” a Lufthansa plane.

(According to the senior aide to Germany’s interior minister, it is ”probably true” that the ”hijacking” was orchestrated as part of a German-Palestinian scheme to free the terrorists.) It was the German decision to free these killers to kill again that strengthened Golda Meir’s resolve to take the steps necessary to protect her citizens, but you wouldn’t know that from watching ”Munich.”

Alan Dershowitz is a professor of law at Harvard. His latest book is ”The Case For Peace: How the Arab-Israeli Conflict Can Be Resolved.”