The recent, tragic attacks in Paris - and the heightened security situation that has inevitably followed - has of course thrown up the question of whether the police and the security services have enough powers to deal with the threat posed by extermist violence.
An open and shut case, you might think. It's understandable for the public to be worried; for law enforcement agencies to try to do everything they possibly can to stop such atrocities; and for governments to listen to both.
Except for our old friend: unintended consequences.
Now some of the proposals announced recently, in particular by UK Prime Minister David Cameron, are eminently sensible. More resources for the security services. Joint cyber warfare trials, or 'wargames', with the Americans.
And there's plenty more that everyone can have an opinion about, but that's still in the realm of contestable, arguable, testable data and good sense. And that was already floating about in the public policy arena, either in Bills presently before Parliament or in draft proposals by Ministers. Should IP matching be brought in, to make sure that the police can see who's using an any one device at a particular time and place? Should the police and the security services be able to see the 'headers' of your email traffic, basic details about the websites you've looked at, and who you've phoned, for the last twelve months - excluding the actual content of those communications, which would have to await a warrant? Well, we'd argue probably not, and we have good authority: the Deputy Prime Minister himself has just declared such measures to be 'un-British' (whatever that means). But it's at least worth having the debate.
What is not debatable the desirability and practicality of another item on the Prime Minister's wish list: banning encryption, the process by which messages are unbreakably encoded by the senders.
It can't happen, so it won't happen. Forcing big social media companies to keep information sounds big. It isn't, because it's impossible. Apple now makes its iMessage content unreadable and unsaveable by anyone except the sender, so good luck with getting the suits from California to hand stuff over - since they don't have it themselves, they reside in an entirely different legal jurisdiction, and they can't be touched by UK law.
There might be a tiny bit of efficacy here, if a crackdown on established social media sites pushes some violent extremists out of those easy-to-use and easy-to-access spaces, and into the open. But the much more likely outcome? All that open source encryption software out there will just mutate more quickly, more punishingly, and in ever more complex ways, allowing even more anonymous communications. It's the same set of paradoxes that undermines the case for 'we must keep everything' in the first place: in fact, the first line of defence against terrorism is properly integrated human intelligence, done well. A massive flood of data from almost every side might make things worse, because the haystack in which the needle sits would just get bigger and bigger. Even tech-savvy Conservative activists are hanging their heads in shame and muttering about becoming seen as 'the stupid party'.
Do we really think that everyone else, from absolutely every other country in the world, will really leave their encrypted devices at Passport Control? Can we make them hand them in? Do we want to open up a great big back door in all our communications, just ready for hackers and criminals (who understand this world much more clearly than do the authorities) to pour through? Do we want to endanger our world-beating industrial lead in software design, secure banking and academic security research? It's just really pitiful, ill-thought-out mush. In the bin it goes.
Anyway, it's all part of a bigger picture. What is so worrying about this simple dunder-headedness is that it is part of a pattern. Of a Prime Minister who inhabits a fantasy land of 'I want this to happen, so it must'. Of a civil service that has been so denuded of wise old heads, and is overworked and demoralised, that they can't even tell the wood from the trees any more.
Over the last year or two 'Public Policy and the Past' has dissected a whole raft of government policies that are never going to happen, that should never have been talked about, or that should never have been launched. Remember those checks that landlords were going to make on nationality? Remember Universal Credit (no further explanation required)? Remember the 'scientific' basis for the badger cull? Remember the laughable attacks on the European Court of Human Rights, and the massive tax cuts that will supposedly follow a Conservative victory in the upcoming General Election?
Shredded. Every single one. Just like this ridiculous, absurd and embarrassing proposal - just the latest doomed to sink without trace.
