My colleague Tobias Feakin suggests that the discussion about any balance between security and civil liberties is inadequate for analysing counter-terrorism measures: it leads to ‘the establishment of rigid political positions which tend to overlook external perspectives—especially those of the public’.

Toby says that concepts of ‘balance’ have contributed to the widespread assumption that the relationship between the two can be considered as a ‘zero-sum’, and ‘that the balance model misunderstands the complexity of the relationship between security and civil liberties’.

I beg to disagree. The world is full of constraints: in a practical public policy sense, democratic governments will always need to balance national security objectives with civil liberties.

We can’t avoid the question of where the best point of balance lies because the two claims, both in law and policy, will always have some degree of tension between them.

One claim won’t always defeat the other, so we do have to try and work out some balance (and this isn’t just a ‘splitting the difference’ exercise.)

It’s true that security and civil-liberties values and goals can sometimes both be maximised, but in practice it’s hard to think of cases where we won’t need to come to a judgment on where the balance lies.

Perhaps the most controversial recent example was the publication of the materials by Edward Snowden that raised basic questions about whether some security materials should be published.

I suggested in a recent op-ed on data retention that in making judgments on the balance here between security and privacy, there will be a need to adjust to the security situation we face at a particular time: we should permit a greater degree of tolerance for national security measures if the threat level goes up.

In striking the appropriate balance in our legal and policy measures for countering terrorism we should avoid excessive swings of the pendulum. (But there’s no doubt the pendulum’s swing will change over time.)

We must always compare the gains we make in national security benefits against any real harm done to our civil liberties.

Anthony Bergin is deputy director of ASPI. Image courtesy of Flickr user Shannon Kokoska.