It has become something of a truism – albeit not one widely acknowledged by its advocates – that constitutional reforms seldom if ever have the effect intended by their architects.

Rob Ford sums it up nicely: devolution didn’t stabilise the constitution, improve governance, or weaken nationalism; the EU referendum hasn’t settled the issue (yet?); and the Fixed-term Parliaments Act has perversely strengthened the executive.

To this sorry list of ill-judged innovations, which might also compass Lords reform and, in time, the establishment of the Supreme Court, we must surely now add the ‘Meaningful Vote’, and by extension the broader idea that the executive’s traditional authority to conduct foreign relations should be usurped by the legislature.

Of course, this can seem counter-intuitive from the immediate perspective of a Brexiteer. Had Europhile MPs not extracted the Meaningful Vote from the Government, Theresa May would have been at liberty to conclude any deal she liked with the European Union. In tactical terms, the European Research Group certainly owe them thanks.

But as a rule it is best to avoid basing constitutional judgements on whatever immediately benefits your own team (*ahem*), and the charge that the UK’s negotiators aren’t being taken seriously is worth thinking about as we head towards a future which involves negotiating lots of new trade agreements and other treaties.

For all that Twitter likes to mock the Prime Minister for trying to ‘tear up her own deal’, her doing so is the logical consequence of the new regime MPs have imposed upon her. Yes, her team negotiated the version of the ‘backstop’ she then whipped Tory MPs to seek to scrap via the Brady Amendment. But the House of Commons had just overwhelmingly rejected her deal in terms which made clear that the backstop was the sticking point. What was she supposed to do?

And if the need to get the deal ratified by Parliament – not just through the Meaningful Vote but then through a specific Withdrawal Agreement Bill – didn’t completely undermine the Government’s position as negotiator, the Grieve/Cooper bid to have the House of Commons somehow take direct control of the negotiations would have finished the job. Such a move would effectively have given us a parallel, single-issue executive with whom Brussels would, presumably, have ended up negotiating instead.

Unlike some, I don’t believe that much of the political chaos of the last couple of years is necessarily a bad thing. The country is undergoing a jarring political adjustment, and there’s nothing wrong with a constitution which lets that process play out in the political arena rather than masking or smothering it.

But we should not allow the horror of the executive branch which seems to be nurtured by many constitutional reformers to leave us with arrangements which straightforwardly don’t work.

MPs can scrutinise and defeat Government legislation, investigate issues through select committees, and hold ministers to account in the Chamber. But there are some matters, including war and the conduct of foreign relations, to which the legislature is simply ill-suited, and where it performs badly when it oversteps its traditional role. It is not the case that any increase in the power of the legislature is a good thing.

Likewise, the supremacy of the Commons in our constitution comes from its ability – sadly hindered in fact, if not in theory, by the FTPA – to sack the Government. It has never rested in an ability for the mere balance of opinion amongst MPs to carry the day on an issue-by-issue basis – just as ‘parliamentary sovereignty’ applies to the will of the whole institution (Lords, Commons, and Crown), and does not imply that MPs alone must have a binding vote on this or that specific measure.

The Government can only be held accountable by the voters – or taken seriously by foreign counterparts, whether we be offering trade or armed intervention – if it has the powers to pursue its agenda.

The case for the executive must be made, and an urgent scheme of constitutional repairs (including, finally, the repeal of the FTPA) should be part of any post-Brexit Conservative programme. “Absolute monarchy regulated by regicide” is an analogy familiar to Tories in the context of our own leadership, and a similar principle remains the best means of reconciling effective government and democratic accountability in our constitution.