‘Sovereign is he who decides on the exception,’ Carl Schmitt famously wrote in Political Theology. Article 48 of the Weimar Constitution, which so excited Schmitt, invested the president with emergency powers. After they came to power in 1933, the Nazis duly got president Hindenburg to use article 48 to annul constitutional rights in the wake of the Reichstag fire.

Executive fiat survives intact in today’s democracies. In the UK, Orders in Council persist as executive powers with the force of primary legislation, exercised under the royal prerogative – they were used in 2004, for example, to overturn a court ruling that the forcible exile of Chagos islanders was unlawful.

The 2004 Civil Contingencies Act grants ministers the power to decide what counts as an emergency, ‘in so far as an event or situation involves or causes disruption of a specified supply, system, facility or service’. On this basis, ministers could rule that the country was in the grips of an emergency if milk deliveries got disrupted. The CCA at least incorporates these goalpost-setting powers as part of its rubric. Elsewhere, it seems, appealing over the law to warm popular sentiment gives the executive all the scope that Schmitt could have wanted.

Tax law, for instance, seems to have become a matter of sovereign decisionism. This week the Times has been going after tax avoiders, including the comedian Jimmy Carr. It’s undoubtedly gutting that a man who makes upwards of £3 million a year can whittle his income-tax exposure down to 1 per cent via offshore wheezes like the K2 scheme. And so, after taking a quick glance at his moral compass and the headlines, David Cameron denounced Carr’s tax avoidance from the G20 summit in Mexico as ‘morally wrong’. Now the government is prey to the press’s open season on tax-scamming Tory supporters and donors, not to mention the Cameron family. Challenged on his silence about the tax-dodging Tory supporter Gary Barlow, Cameron went all Schmittian, saying that he’d whacked Carr because the case was a ‘particularly egregious’ one, for which he had ‘made an exception’.

The PM didn’t say exactly what he had made an exception to, but one plausible candidate would be the rule of law. No one’s likely to shed too many tears for Carr’s wallet, but larger issues obtrude: his dodge via the K2 loophole is accepted by all sides as legal. Thomas Hobbes, not often acclaimed as a liberal, said that citizens’ liberties depend on the silence of the law. Nowadays liberty seems to depend on the silence of the tabloids. The trouble with cheering on Cameron as he sticks it to Carr – useful in buffing up the PM’s demotic cred after ditching the 50p tax rate – is that it tends to stifle complaints about executive breaches of the law elsewhere.

Sovereign exceptionalism offers a useful way of overriding democratic norms when the plea of emergency lies to hand. The US has baulked at ratifying the 2002 Rome Statute creating the International Criminal Court, which was set up to implement the principle of universal jurisdiction. The Obama White House upholds, however, a principle of universal extrajudicial execution, via its use of drone attack-bots to bump off suspected badhats across the Middle East with inevitable ‘collateral damage’, i.e. killing civilians (estimates vary between 800 and 4000).

Obama’s administration has come up with a useful method of cutting civilian drone killings – redefining ‘combatants’ to mean all military-age males. This is handy in laundering such incidents as the killing last year of the 16-year-old son of al-Qaeda suspect Anwar Awlaki by a drone in Yemen (Awlaki himself had been killed a couple of weeks earlier). Reason of state waives the rules, be it to vindicate drone attacks, or taxes on drones. Those outside the Beltway, though, should avoid abetting regimes that make free use of what Jeremy Bentham called ‘anarchical fallacies’.