Politically, Mr Straw's motives are obvious. He is building on his predecessor Tony Blair's slogan "tough on crime, tough on the causes of crime", which has done much to reassure the public that Labour cares about the victims of crime and social disorder and helpfully to dispel any idea that crime is mainly a problem faced by the better-off.
Mr Straw's latest contribution to the debate, however, contains three serious errors. First, and most garishly, it comes close to endorsing a police-led drive to clear the streets of undesirables. The water-cannon approach to keeping cities tidy, favoured in parts of Europe, is one we can do without. At best, it would transfer the problem. Sure, the boulevards would be spotless, but the alleys would be foul.
Error two is the way the speech muddles the important and the trivial. Homelessness and drug addiction are chronic, complex problems. Freelance windscreen-cleaning is scarcely a defining aspect of a Blade Runner society; or if it is, why not also the boy selling the evening paper or a bunch of roses to homeward-bound motorists stuck at traffic lights? Graffiti? Well, let's come back to that.
Mr Straw's most grievous error is the shallowness of his (and his party's) thinking on these matters. Take drug addicts. An effective response to this problem requires at least the following components: an up-to-date view of where the boundaries of legality and illegality should be drawn; effective policing on that basis; and properly funded, highly intelligent, community-level agencies capable of establishing a relationship with this marginalised group of people. Only an agency of this kind has any hope of improving the lot of drug abusers, or getting them off the streets, or reducing the amount of crime they commit in order to support their habits. Improvement comes through negotiation within tenable rules.
Mr Straw will point out that his speech also waxed lyrical about partnerships between police, local authorities and other agencies. But unless politicians are prepared to face these problems in all their dimensions, they will not achieve much. Labour, wanting above all to appear respectable and electable, is afraid to associate itself with undesirables, and that includes any debate about decriminalising possession of some drugs. Likewise, eager to appear solid for law and order, the party proposes impossible roles for the police.
Thus when Michael Howard sticks out his chin and offers us Home Office policy by slogans to do with boot camps and shocks of the short, sharp variety, Mr Straw puffs out his chest and replies in kind. It becomes Howard's graffiti vs Straw's graffiti - unsightly and unhelpful. Time to hand in the aerosols, lads.