Attitudes change as societies open up, and as economic, social and educational prosperity spread, but this happens differently in different places. It is legitimate to be appalled by barbaric practices from which ones own society has moved on, but it does not follow that one can bomb others into change.
We might tell Hilary Benn that a change of mind - even at this late hour - could change votes and prevent the terrible violence that we are about to unleash. Let's ask him, on behalf of all who are gravely at risk from our bombs - in Syria and here at home - to speak passionately alongside Jeremy Corbyn tomorrow. He might wish to tell us how a principled man came to change his mind.
Proof that the British political class hasn't learned anything after Iraq came with David Cameron's ludicrous assertion that there are 70,000 moderate rebels fighting in Syria. It was an outright fabrication to rank with Blair's sexed up dossier on Saddam's WMD, which the then prime minister asserted could be launched against Britain within 45 minutes.
Within the next week Members of Parliament will be voting on whether to launch air strikes against ISIS in Syria. With many Labour and Conservative MPs in support of extending air strikes into Syria, it is likely that the first bombing raids will take place towards the end of next week. But it has not been determined what the government wishes to achieve by bombing Syria.
I want to make clear that whatever the outcome of the discussions, I will be voting against Syrian intervention. For some, air strikes in Syria can be justified solely on the basis that we are already launching air strikes against the same foe in Iraq. This vote, in their minds, is a mere extension of the war against ISIL to another country.
In a lengthy and in depth discussion at the Cardiff West Labour Party monthly meeting last Friday we agreed that there were no easy moral certainties over the debate on Syria. Those on either side of the argument who see the question of what is the right thing for the UK to do in black and white, ignore the fact that this is not a question of war and peace.
When someone attacks you or yours, you strike back and you strike back hard. That is not just the natural, instinctive response - it is the right and moral course of action. Failure to do so betrays a fundamental lack of self-esteem; if your own life and the lives of those you love are not worth defending, what is?
When military action against Daesh is brought up, the reminders of Iraq are almost inevitable. The many mistakes and the arguably illegal steps leading to the disastrous decade-long war have led to innumerable doubts in the minds of voters and of MPs as to whether to be in favour of, or against action in Syria. Ultimately, no one is rightly keen for history to repeat itself.