Most people won’t even be unpacking the world’s smallest violin for Reyaad Khan and Ruhul Amin, the two jihadis who traveled from Britain to join ISIS in Syria.

I certainly won’t shed any tears – Khan and Amin joined this terrorist movement in the full knowledge that they were signing up to a totalitarian, genocidal, gay-killing gang which openly operates a market in slaves. They chose their side in a war not just on Yazidis, Kurds, Christians and non-Islamist Muslims, but on this country too. That the other side shot back should be no surprise or offence.

There is a legal debate underway about the decision to kill these men, but the Government’s case seems both clear and correct. As Joshua Rozenberg explains concisely in the Guardian, as British citizens planning attacks against Britain, it was lawful for the Britiah Government to kill them in self-defence.

With both the right and the law in agreement it seems unlikely that Labour’s hand-wringing over the decision will get very far.

But there is a political aspect to the news, particularly given Michael Fallon’s (justified) comments that he would make the same decision again in future.

We now have a new, broad consensus that Parliament ought to vote on Britain going to war. There’s no real constitutional basis for the idea, but it’s one that has been backed by all the main parties – and there is clear popular support for it. In an organic constitution that’s how conventions are made.

Was this drone strike a breach of that newly-minted principle?

No, because this wasn’t an indiscriminate air campaign against the whole of ISIS in Syria, it was a targeted act of self-defence against people of British origin planning attacks on Britain.

No also because no-one has seriously suggested Parliament entirely bind the Government’s hands when crisis calls. If Fallon stood up in the Commons and gave away the details of a planned strike in advance, the targets would obviously absent themselves from the strike’s intended location. Remember that even the Libyan intervention was only voted on after it had started.

No finally because Cameron has still placed the matter before MPs now the deed is done and Parliament is reconvened. He has submitted the decision for scrutiny in a way that no U.S. President has done for a far larger and less precise campaign by American forces.

There will now inevitably be a debate about a wider campaign of air and drone strikes against ISIS in Syria. That debate is overdue, and it will no doubt take place in Parliament, in the press and in the pub before MPs vote on it.

That is not to say such a vote has a certain outcome. This new principle places huge pressure on the Attorney General in producing the Government’s legal advice. It is also subject to unpredictable events – as Miliband’s about-turn in the last Syria vote demonstrated. And it may prove vulnerable, too, to misgivings on the Tory backbenches.

This final point is crucial. Last night’s purdah vote was a painful reminder for Ministers that they are reliant on a slim majority. We already know there are several sceptics of military intervention on the Conservative benches – if this drone strike leads to them being joined by those concerned about the legal process of such killings the next Syria vote could fail like the last.