There are precious few constants in history and humanity. The only real certainty is that everybody dies eventually, and frankly that's not a great starting point for public policymaking.
However, the other abiding rule is that order is better than chaos. Even societies that function appallingly are safer and stronger than societies that do not function at all.
The great Roman historian Tacitus famously declared of his empire: "They make a desert and call it peace." This was meant as a darkly ironic condemnation and yet the very time and place in which Tacitus was writing — the century of the so-called "Five Good Emperors" — was argued by many later historians to be a golden age of human history.
Countless peoples had been killed, conquered and enslaved to achieve this but for those who survived and generations of their offspring, the result was an unprecedented era of peace and stability after the constant bloody churn of war.
Even during the darkest abomination in human history — Hitler's Holocaust — the rule still held. As hideous as it is to compare, it was often safer to be a German Jew in Nazi Germany than it was to be Jewish in the lands the Nazis conquered and marauded.
As the Holocaust historian Timothy Snyder recently documented, it was where governments were toppled and citizens were instantly stripped of their rights that Jews and anyone else the Nazis wanted to get rid of were easiest to wipe out.
Hence it was in the stateless and lawless Nazi-occupied lands of Eastern Europe that the most industrial-scale genocide occurred, rather than in Germany itself.
In other words, even a place with an evil government and evil laws was marginally less dangerous than a place with no government and no laws at all — because there, evil could sweep through entirely unchecked.
This is a horrible reality to confront but it is a reality we need to remember if we are to avoid repeating it. And it is this that brings us to the brutal mess of the Syrian civil war, which has caused the greatest dispossession of human beings since Hitler's death. Hundreds of thousands have been killed and millions driven out of their homelands.
This story has many victims, many villains and precious few heroes but if any group of people could lay claim to that last elusive honour it would be the very people who the West has just abandoned.
In 2013, a subhuman sh*t stain called Abu Bakr al-Baghdadi declared himself the leader of the Islamic State of Iraq and Syria, the most extreme terrorist organisation in history. This was a group that delighted in death and went to limitless efforts to find more grotesquely terrifying ways of causing it.
The Kurdish people of northern Syria and Iraq, who had already struggled for years against the dictators of those countries, now found themselves face-to-face with a terrorist army in the heart of their homeland. Unlike any of the other forces that would eventually unite against ISIS, the Kurds had no foreign shore to return to and no capital to retreat to.
And so, with a combination of courage and desperation, they did the only thing they could: They fought.
And they fought well. As it turned out, the Kurds were extremely good at killing terrorists. They knew their enemy, they knew the landscape and — most vitally — they had no choice.
When the motley coalition of undercooked Iraqi soldiers, double-dealing Russian and Iranian-backed Syrian forces, US military "advisers" and various other Western and Arabic players eventually went in to bat, it was the Kurds who had the most invaluable intelligence and tactics in taking out this army of dumb murderous thugs.
As a result, we beat the b**tards.
We put the foot on the throat of ISIS and managed to cauterise the bloody wound they had slashed through the cradle of civilisation.
And then, as they were mopping up the mess, we left them to die.
Because even as the Kurds were still fighting for recognition from Iraq and Syria, they faced an arguably greater threat from Turkey, a fiercely nationalist nation that sits at the nexus of Europe and Asia and sees the Kurds as terrorists themselves.
And a nation that is now in the hands of a dictatorial hardman cut from the same cloth as Hussein and Assad but can still claim to be a member of NATO.
Indeed, the only fig leaf of protection the Kurds have had from the Turks in recent years has been the fact they were working with the most powerful country in the world to wipe out the most powerful terrorist threat in the world. And then, that country just packed up and left its greatest friends in their greatest hour of need.
Now obviously this is not an exact military history of the events leading up to Donald Trump's infantile decision, but it is an exact moral one. His decision is not only a strategic disaster but a national disgrace. It is a complete abrogation of American honour.
As any reader knows, I am far from a kneejerk Trump hater. While I certainly never anticipated or supported him, the only thing more ridiculous than his presidential win turned out to be the hysteria that followed it.
Indeed, one of the most fascinating things about Trump is how his irrationality often exposes the irrationality of his opponents. Another is how his know-no-rules approach tests dusty political assumptions.
It is possible, for example, that he has slowed the once-inevitable ascendancy of China by being so volatile and unpredictable that the Chinese will be unable to fully consolidate their global supremacy before their own ageing population constrains their economic power.
Maybe he knows what he is doing and maybe he doesn't, yet it is hard to argue that a more cautious China isn't a net benefit for the globe.
But the fun of watching a rogue pinball bouncing around staid geopolitical norms is very different to a dumb decision that destroys lives with immediate and devastating effect.
Cutting loose the Kurds is simply an act of dumb b**tardry, an act so strategically and intellectually bankrupt that it consigns to the scrap heap the theory that Trump is some kind of idiot savant with a secret method behind his madness that only his most ardent admirers can retrospectively divine.
Zealots argue that Trump is just doing what he promised and getting American troops out of the Middle East and withdrawing the nation from foreign wars. But if that is so, then why now and why here? It is both the worst possible place and the worst possible time.
Moreover, it comes almost three years after his election, two and a half years after he launched a missile strike on Syria, two years after he threatened to blow North Korea to Coventry and he is now in the midst of declaring some weird economic war on Turkey for doing precisely what his actions enabled it to do.
If this is a pacifist foreign policy then John Rambo is Mahatma Gandhi.
A stronger argument is that the US should never have invaded Iraq in the first place — which arguably created the power vacuum and Western imperialist narrative which al-Baghdadi was able to exploit — and Trump is just fixing past mistakes.
But the problem with that is he is not fixing them, he is fuelling them. Having come within a cigarette paper of choking out ISIS completely, he has now allowed hundreds of ISIS fighters and associates to escape and turned an uneasy peace into open war.
In suburban terms, this is like breaking into someone's house, taking a dump in their fuse box and then disappearing over the back fence — only to protest it was never your fuse box in the first place.
This brings us to the most bizarre defence of all. Some Trump supporters have pointed to the Facebook posts of the infamous Orlando nightclub gunman suggesting he was seeking vengeance for US air strikes in Iraq and Syria and that this withdrawal would avert such future killings.
Now call me crazy, but I seem to remember a time when the great nation of the United States had a pretty famous policy of not negotiating with terrorists. And now its most fervent patriots are saying the only way to "Make America Great Again" is to do whatever the terrorists want. Not to mention letting the terrorists run free.
Honestly, when will this bulls**t stop.
Meanwhile, back in Syria, the Kurds have been forced to turn to Assad's murderous regime for protection against Turkey because apparently the only thing safer than the country that wants to kill you today is the country that wanted to kill you yesterday.
The fearless are now helpless. Worse still, they are stateless, literally caught in the crossfire between two nations who would rather they didn't exist.
This is precisely the chaos in which the most deadly evil thrives.
The quintessential troubadour of Australian morality John Williamson once sang that the definition of being "true blue" was standing by your mate when he's in a fight.
The Kurds are literally fighting for their lives and thought they finally had a mate in the US and the West. But now instead of standing we're running.
That's not true blue. That's blue murder.