Last week, in this column, I wrote about the question of whether it was ever appropriate for a government to take military action without prior parliamentary approval.
At the time when I wrote that article, we did not know exactly what action the government, in concert with the French and US governments would take in response to the chemical weapons attack in Syria. We now know, of course, that the action was rapid, self-contained, highly targeted and aimed at degrading chemical weapons facilities whilst minimising any collateral damage and avoiding loss of civilian lives.
At the time when I was writing the previous column, we also did not know whether Parliament would give majority support to the action retrospectively. We now know that there was a considerable majority in parliament in favour of the action once it had occurred.
There was, however, a very interesting debate about the specific topic that I raised in my last column - namely, whether the government should have sought prior approval.
On this, too, it turned out that there was a majority in parliament who took the view that, in this instance, there was not any need for the government to seek prior approval. But what was very interesting was the degree to which, in the course of the debate, distinctions began to be made between different kinds of action under different circumstances.
It became clear that everybody in the House of Commons agreed that, in the event of a direct attack on the UK, it would be both permissible and indeed obligatory for the government to act immediately in whatever way would best protect us, without first consulting parliament if that would involve the slightest delay or distract the government from focusing on the effectiveness of the response.
At the other end of the spectrum, it seemed to me almost universally agreed that, where a government was proposing a long-term series of military actions which would or might involve putting large numbers of lives at risk and which might be difficult to unwind in any short period, there was a clear need under the existing conventions for parliament to be consulted in advance and to give its approval (only one Member of Parliament made a speech defending the pure and ancient doctrine that the government could engage in such prolonged warfare on the basis of the Royal Prerogative power and subject only to the requirement to continue commanding the confidence of the House of Commons). However, between these two extremes there was an interesting and as yet unresolved debate about the threshold at which prior parliamentary approval would be required. In this grey area, there were many different views about what the current convention really means - and hence about what the constitutional position currently is or ought to be. We are seeing our constitution evolving before our eyes.