The conviction of Shahawar Matin Siraj on conspiracy charges for plotting to blow up the Herald Square subway station marks more than a victory in the war on terror. It is also a vindication of the efforts of Commissioner Raymond Kelly and New York’s Finest in their efforts to protect the city from future acts of terror. The commissioner has taken heat in some quarters for some of those tactics, such as developing his own sources of intelligence abroad and using undercover officers in the city. The Siraj conviction demonstrates a jury of ordinary New Yorkers understands.

The investigation that led up to this week’s conviction marks one of the greatest successes enjoyed thus far by the police department in its effort to apply more traditional policing techniques, like the use of undercover officers and informants and encouraging tips from citizens by building good relationships with the neighborhood, to the new challenges posed by the terrorist threat. A debate still rages over whether terrorism is best treated as a law enforcement problem or a military matter, but this case transcends that. Rather, it shows that there is a need for all agencies at all levels to remain vigilant.

After September 11, Mr. Kelly had the foresight to realize that New York couldn’t rely on federal authorities alone to protect the city and moved to use the law enforcement tools at his disposal to do as much as possible to detect potential threats. The cause for congratulation here is that the department is now finding ways to get leads from people who can alert police to potential terrorist plots. That marks major progress for the city, and Commissioner Kelly deserves credit for the creative thinking and resourceful policing that have made it possible.