A Minor Constitutional Earthquake

In constitutional terms, Tony Blair could be described as the gift that keeps on giving. Having failed with the alternative vote and reform of the House of Lords, last night’s seminal vote on Syria means that David Cameron and Nick Clegg have enacted a major constitutional reform, albeit probably not as they intended. On behalf of the current and future members of the Executive branch, they’ve relinquished the power to engage in wars of choice.

This is remarkable.

Since Walpole was Prime Minister to George I at the dawn of the modern British State, the settlement of powers between the Executive and Legislative branches of Government have waxed and waned depending on their comparative strength and the national and international situation. Since 1721, however, one set of Royal Prerogative powers has remained firmly in the hands of the Executive: the power to go to war.

Yet absent an immediate threat to the UK, our overseas territories or to our allies covered by mutual defence treaties (notably NATO Article 5), it is now hard to conceive of circumstances under which a British Prime Minister would order British forces to battle without the explicit prior consent of the House of Commons. Indeed, to do so today would appear to risk a constitutional crisis. Better, for international law, there appears to be a new norm to publish the legal advice on the use of force, and a need for express legality from the United Nations or through the emerging Responsibility to Protect doctrine.

This matters.

For a nation with an unwritten constitution, precedence and practice – combined with some national and international statutes – provide the rules of the political game. If the Executive cedes power to the Legislature or to the devolved administrations, it is unlikely to get it back – and never more than in this case.

How did we get here? The 18 March 2003 vote on the invasion of Iraq was the first time that the Government allowed the Commons to decide whether or not the UK would go to war. In the 2003 vote, the Labour Government majority was provided by the support of the Conservative opposition; the invasion began the following day. And if 2003 provided the opening for the change, then last night’s debate provided the dénouement: when the House of Commons voted against action, Britain was unable to follow the course that the Government of the day was apparently set on.

So despite the warm words of David Cameron in opposition and of Gordon Brown in office, it has fallen to the Commons to take what the Executive failed to enact. In doing so, the House of Commons has asserted a much greater crimp on Executive power than the famous US Congress War Powers Act (WPA). Enacted over Nixon’s veto in 1973 the WPA requires the US Executive to notify Congress of the introduction of US armed forces into hostilities or “situations where imminent involvement in hostilities is clearly indicated by the circumstances” within 48 hours, and the gives the Executive up to 90 days to secure Congressional support or to terminate the US armed forces involvement. Britain’s new constitutional settlement for wars of choice doesn’t even give Britain’s Executive this flexibility in future.

There will be those who downplay the scale of these changes, noting that Britain's unwritten constitution is inherently flexible, and that the irreducible element is whether a party can command a Commons majority for its budget. This remains true, but the counterfactual to consider is whether David Cameron could survive ignoring Parliament to join a US-led attack on Syria regardless. The fact that this is now politically inconceivable underscores just how much the Constitutional position changed last night; it will be fascinating to see how this develops.

But make no mistake: reports of a constitutional earthquake last night were entirely accurate.