To those of us whose political consciousness was shaped in the 70s and 80s, reaction to the detention of David Miranda has been a little puzzling.
What I mean is that back then, Conservatives dominated the rhetoric of freedom - so much so that a reputable publication headlined Thatcher's obituary simply "freedom fighter". However, Thatcher's spiritual children are certainly not fighting for freedom. The best that can be said for Theresa May's defence of Miranda's detention is that she's prioritizing security over liberty, the worst that it is an attack on essential freedoms of speech.
The Tories aren't alone here. Nick Clegg, allegedly a liberal democrat, has sided with May.
Why, then, are the parties that once prided themselves on their love of freedom defending its abridgement?
One possibility is simple hypocrisy. The Tories' love of freedom in the 80s was always partial; it was freedom for capitalists they favoured, not freedom for all. This hypocrisy is not confined to the right. The left's love of freedom is also equivocal, being stronger for social freedoms than economic ones.
Another possibility is that Ms May has been captured by vested interests. Basic public choice economics tells us that the police and security services, like all bureaucrats, want to enlarge their budgets and prestige. One way to do this is to exaggerate the threats to "national security". And after months of lobbying in this fashion, bureaucrats are likely to capture their ministers.
For my purposes, it doesn't much matter which of these possibilities applies. Both have the same implication - that freedom has few powerful defenders.It is either abandoned when it no longer serves a sectional interest, or it loses out to budget-maximizing bureaucrats.
It's in this context that Marx (and Thatcher!) saw something which libertarians don't - that social change requires not just intellectual arguments but some agents to drive it through; Marx thought these agents would be workers, whereas Thatcher ensured they were (some?) capitalists. This poses the question: who, now, are the powerful agents who might push for freedom? (If you think the answer is capitalists, you're a fool.) What Stalin asked of the Pope - "how many divisions has he got?" - can equally be asked of freedom.
Politics is shaped more by material interests and power than by abstract principles. The problem is that these interests are at least sometimes hostile to liberty.