The new Machiavelli

Should the state take action against people who have done nothing wrong, if there are plausible grounds for thinking that they are about to? Suppose, says Alan Dershowitz, that reliable intelligence shows that a large-scale terrorist attack is about to happen. Should the law allow the police to round up whole categories of potential perpetrators in advance, in the hope of stopping the conspiracy in its tracks? Should it authorise the use of torture to obtain information that will prevent the attack? What if the suspected mastermind is identified in a foreign country where the authorities are too weak, wicked or incompetent to arrest him? Might one assassinate him instead? Or invade the foreign country? Or bomb it from a great height?

These are ancient dilemmas, but it has taken the events of the last five years to bring them to the forefront of political debate. Even now the public, although largely in favour of pre-emptive action, is reluctant to contemplate its implications.