The Italian government seemed to be defining moderation when it resolved on Wednesday to bear down on terrorists, but only in a conventional tempo. The alternative was to take drastic means to ring in the proposed changes.

These would permit police to hold suspects in detention not for 12 hours, but for 24. The measure would also permit the security detachment to archive e-mail communications for unspecified periods of time. The authority of government to expel illegal immigrants suspected of conniving with terrorist groups would be enhanced.

The minister of the interior, Giuseppe Pisanu, found just the right language to do two things, the first, to call for the adoption of the new measures; the second, to decline fast track parliamentary action. “The evaluation of circumstances and converging hints,” he said, “push us to think that such a thing is possible.” By “such a thing,” Mr. Pisanu means: a terrorist attack.

It had been a stunning 24 hours. The British identified all four of the men who had detonated the bombs in London. The examination of the culprits was extraordinary in its completeness. Consider Shehzad Tanweer. He was 22 years old, and his father operated a fish-and-chip shop in Leeds. Shehzad went to college in Leeds majoring in sports science. He was a cricketer who trained also in tae kwon do and judo.

A friend who knew him well stepped forward immediately to say that “Shazzy is the best lad I have ever met. He’s a top guy and a top lad. We play cricket together. He’s a bowler and a batsman. He wouldn’t do anything like this. He’s from a very strong family. … Shehzad is a very kind person who would get along with anyone and anybody. He’s the kind of guy who would condemn extremism” – and engage in it.

The very same day that Shehzad was identified, the Dutch released the spoken testimony of another young Muslim, Mohammed Bouyeri, who is 27. Last November, Bouyeri shot Dutch filmmaker Theo van Gogh eight or nine times and then slashed his throat with a knife. In court, Bouyeri was anxious to make one thing very clear: “I acted out of conviction and not out of hate. If I’m ever released, I’d do the same again. Exactly the same.” He was not to be hurried on the point. “I don’t feel your pain,” he told van Gogh’s mother, who was sitting in the courtroom. “I don’t know what it’s like to lose a child that was brought into this world with so much pain and tears. I realize that my attitude is very confrontational for you and others. I hope that you will derive some comfort from the maximum sentence.”

So it isn’t that Bouyeri is indifferent to the question of giving comfort to others. He authorizes us to take satisfaction from any severity to which the court is given in its sentence.

The two assailants leave Westerners without speech, and terribly hard up for useful thought. It is hard to imagine better care or more opportunity than was given to the 22-year-old Englishman, or greater tolerance than was given to the after-the-fact rhetoric of the Dutchman. We are apparently left with nothing better than the bumbling of the Italian minister of the interior, who acknowledges only the need for “the evaluation of circumstances and converging hints (which will) push us to think.”

The first thought, surely, has to be that not all young Muslims at large in Europe have a viral compulsion to put bombs in London subways or to shoot and stab provocative filmmakers. So having arrived at that thought, what is our next thought?

It is not highly developed, but it focuses necessarily on acute security measures. They mount aggression, we mount a defense. This is bitter medicine in that the countermeasures signal a victory for terrorism.

London withstood years of bombings organized by a sovereign madman who came to control Germany. That threat, on reflection, seems simple: Cope with it by waging a world war. We know how to do that. We don’t know how to abort the evolution of young Muslims into murderers.