It is also important to deny to sympathisers and possible imitators of the suicide bombers the encouragement of being regarded as part of something great, potent and global. We must remember that these are sad, deluded and un-balanced people whose end was grisly and pointless. We should not glorify them - in the word shortly to be inscribed in the statute books - by pandering to their self-perception as engaged in a purposeful and well-organised struggle. The failure of the 21 July bombings was a huge gain for civilisation, in that the protagonists resemble the bumbling fools in Conrad's The Secret Agent.
I tend, therefore, to the unalarmist end of the spectrum. Mass murder in rich Western countries is technically and logistically very difficult. Gerard Baker in The Times, the day after the 7 July bombings, took a perverse satisfaction in asking: "Is this the best they can do?" Yet I cannot shake off the Prime Minister's observation, one he has made consistently since 11 September 2001, that if the suicide hijackers could have killed 300,000 instead of 3,000 in New York, they would have rejoiced. If the London bombers could have killed 5,200 as easily as 52, they would have done.
I am glad, therefore, that Tony Blair puts himself at the opposite end of the spectrum to me. It is all very well for me to decide that the risks of terrorist attack are small, and a price worth paying for the joys of city life. But it is his job to worry that I have miscalculated the risks and to fear the worst.
So, no, I will not join in the strange chorus of tender concern for the human rights of such odious people as Sheikh Bakri Mohammed. The Prime Minister has been much criticised for his 12-point plan, which he unveiled while I was away. Having missed the start of the story, I formed my first impression of his proposals from the media reporting of how it was all unravelling under furious attack from the judges, Shami Chakrabarti and John Humphrys. According to the Today programme, the main purpose of these ill-thought-through measures seemed to be to bully the judges into scrapping every protection of civil liberties enjoyed in this nation for centuries, thus undermining for the first time its pre-eminence as a beacon for the rule of law.
Thanks to the great democratic boon of the internet, I went back and read what the Prime Minister actually said. No doubt, as many commentators say, he held the news conference at short notice, just before going on holiday, in response to hostile headlines. For days, The Sun and the Daily Mail had attacked the feebleness of the Government's response to the terrorist threat and its failure to "kick out" well-known jihadist sympathisers such as Bakri.
Yet what Blair announced was far from draconian. He listed the 12 points and said: "We will consult widely on these measures, including with the other political parties." Only if there were a consensus would he consider recalling parliament in September. The fair criticism of most of the eminently reasonable proposals was, "Why haven't you done it already?", which two journalists did ask. (Blair gently pointed out that in the furious parliamentary debates before the election, the Government was widely accused of exaggerating the terrorist threat.) And the justified criticism of the remainder of the proposals was, "Why don't you go farther?", which nobody asked.
On one point I agree that the Prime Minister too slavishly followed the lead of the authoritarian tabloids. The measures to make it easier to deport troublemakers, followed up by last week's arrests of Abu Qatada and nine other unnamed people, were a knee-jerk reaction to the "kick 'em out" headlines. The trouble is that the tabloid campaign makes no sense. If we are facing a new, international threat from an ideology that animates loosely associated cells of terrorists, how does it make us safer if Bakri is in Beirut rather than in London? As Blair said at the news conference, the internet is "used extensively by people who want to foment this type of hatred". I would rather have Bakri over here so that we can keep an eye on him (and not pay him state benefits) or lock him up if necessary. That is what I understood that the control order regime was for.
Instead of focusing on this illogicality, the reaction to Blair's proposals has been dominated by the idea that the Government wants to bully judges into reinterpreting the Human Rights Act - to allow people to be deported to countries where they may be tortured. This is doubly illogical. The point about the separation of powers is that parliament decides what the law is and the judges apply it to individual cases; if parliament does not like the way judges interpret the law, it can change it. In any case, as Blair pointed out, France and Spain deport people by administrative decision, allowing appeals only from abroad, and they remain signatories to the European Convention on Human Rights.
The real problem, though, is not with foreign nationals - such as Bakri - or people with dual nationality, whose British one could be revoked. We ought now to have moved beyond thinking that jihadist terrorism is something that can simply be "kicked out" and left to fester elsewhere. The 7 July bombers were raised in Britain and three of them were born here. So was Anjem Choudary, the former UK head of al-Muhajiroun, who appeared on Newsnight last week to declare that his allegiance to his conception of Islam came before the obligation to obey British law. "If anyone was going to kill anyone innocent here", he said, he would try to dissuade them, but "it is not allowed to me to co-operate with the police".
When the Home Office first floated the idea of making it an offence to glorify or condone acts of terrorism, it seemed an unacceptable infringement of free speech. I thought David Davis, the likely Conservative leader, had seen it off by asking if the law would have criminalised Cherie Blair for saying of Palestinian suicide bombers: "As long as young people feel they have got no hope but to blow themselves up you are never going to make progress." But I have changed my mind. There is a clear difference between trying to understand suicide terrorism and condoning it. The reaction to Blair's 12-point plan should not be to ask if he has gone too far, but to ask if he has gone far enough.