War against terrorists must be relentless

Confirmation Thursday morning that the suspected mastermind of the Paris attacks was killed in a police raid was calming but also unsettling.

It removed a dangerous man from an amorphous battlefield, and showed that fighting terror is not a hopeless cause. Things can be done to combat such evil. The death of Abdelhamid Abaaoud in Wednesday's raid was the result of good old-fashioned police work. A cellphone was found in a garbage can near the concert hall in which hundreds were killed or wounded Friday night. That led police to an apartment building in a Paris suburb and a siege that resulted in the deaths of Abaaoud and his female cousin, and the arrests of eight other people.

But where was that solid investigative work before Friday's awful attacks? Abaaoud was one of the faces of the Islamic State. He appears in online videos, including one in which he smiles while driving a pickup truck that drags corpses behind it. He was involved in planning several attacks. But European police and intelligence agencies were unable to stop his travels through the continent.

There were other miscues. Earlier this year, Belgian authorities stopped, questioned but then released two brothers who allegedly participated in Friday's attacks -- one is dead, the other at large. And officials never conveyed their concerns to French counterparts, exposing the lack of cooperation between agencies from different countries with open borders that let people easily move between them.

The raid also was disturbing in revealing that another assault was being planned for Paris' business district. It underscored that the fight against terrorism must be aggressive and relentless. Vigilance is essential. Everywhere. Witness the Islamic State video that emerged Wednesday that apparently threatens New York City with a terror attack.

The raid in Paris reminded, too, that U.S. police are handicapped by restrictions on getting information off cellphones. Manhattan District Attorney Cyrus R. Vance Jr. Wednesday called for federal legislation to force tech companies to create access for law enforcement to encrypted information. Such access -- with protections from government abuse -- is important, but cooperation from the industry is better than legislation.

It also is clear that the Islamic State is winning the online war. Not enough is being done to combat a narrative that effectively recruits would-be jihadists around the world. The Islamic State reaches out to disenfranchised young men and offers money, mission, marriage and the power of a mighty caliphate. Now it proudly displays an online photo of what it says the bomb looks like that brought down the Russian plane over Egypt. The fact that the most effective counter-response has come from the hacker group Anonymous, whose members took down more than 5,000 ISIS-related Twitter accounts, is distressing.

The war against terrorism is not easy. But we have to do what we can, to the fullest, always, and never let up. In that sense, defeating terrorists means emulating them.