As every first year constitutional law student knows, in the Westminster system, Parliament (or the Queen-in-Parliament) is sovereign.
There is no question where responsibility for the UK’s leaving the EU must lie – with Parliament.
So the British Parliament exerted its plenitude of sovereign powers when it installed a government pledged to Brexit following the 2017 general election. And when it passed laws setting a leaving date. Also when it rejected the EU withdrawal treaty negotiated by former PM Theresa May. And definitely when it granted supply to the May government and its succeeding Johnson government to keep on trucking.
So what is one to make of Boris Johnson asking the Queen to prorogue Parliament (that is end the Parliamentary session in mid-September and then start a new one after a delay of a month or so – ostensibly to pass his triumphantly-negotiated but highly-unlikely new EU withdrawal agreement).
Well, Parliament is still sovereign but it does need to let the executive perform its legal functions, obey the laws it has made and indeed its own rules. And these include prorogation. So unless the judges go back to ship-money and come up with some new constitutional innovations, then Parliament will have two narrow windows – in early September and late October – to carry through a plan to stop the UK leaving the EU on 31 October without a formal withdrawal agreement.
Herein the Johnson strategy.
Parliament can try to use those time slots to vote no confidence in the Johnson government, install a new government or pass laws seeking to delay Brexit. But what all of these require is that a majority in Parliament comes off the fence and lines up behind a single alternative Brexit policy.
It could be to delay Brexit and have another referendum or general election (with a hand-on-heart promise that this time the people’s will is to be followed). Or perhaps to accept the rejected deal negotiated by Theresa May. Possibly to change course and stay in the EU. Or even to empower Labour’s Jeremy Corbyn to continue negotiating with the EU (although the EU still prefers no-deal to changing the May deal).
Perhaps it does not matter much what the policy is? None of them looks very attractive. Getting a majority looks hard. Prorogation might make it a bit harder.
And if a majority is achieved through the exercise of Parliament’s powers, it would surely be followed by a general election. The election would be a clear fight between Boris’s policy (ie, leave as planned, unless the EU agrees to our eminently reasonable terms) or Parliament’s policy (ie, don’t leave and then ……).
So it looks like prorogation has set things up so Parliament’s sovereignty will be decisively affirmed – it just needs a majority of MPs to decide how to do it.