Imagine if the Iraq War had never happened. What would the world look like now?

For some, the Middle East would be a peaceful region dominated by regional powers in a stand off. It wouldn't matter what Iran, Iraq and Saudi Arabia did to their own people as long as they were in a "Mexican standoff" with each other, pistols loaded and cocked but never fired. That is the "realpolitik" view - the Middle East should be a region of which we hear little and care less.

Thankfully, we did not do that. We did not leave the Iraqi people -- Kurds, Arabs, Sunnis, Shias, Assyrians -- to the mercies of the brutal dictator Saddam Hussein.

This should have been no surprise to anyone who was paying attention. Tony Blair made clear in his 1999 Chicago speech that he believed in liberal interventionism -- a rules-based approach to intervening militarily where necessary.

It is important to remember the background. The Blair government was elected after a Tory government which had sat back and watched ethnic cleansing in the former Yugoslavia -- and done nothing -- and had witnessed genocide in Rwanda -- and also done nothing. The shame felt in Britain about this was real and it fuelled Blair's desire to act differently.

We joined the Iraq War and we were right because that war itself was right.

First and foremost it was a war in defence of the authority of the United Nations. It is often forgotten now but the conflict started because of a sustained defiance of UN sanctions, UN resolutions and ultimately UN weapons inspectors.

It was for that reason that there was a UN Security Council resolution underpinning the actions. Given the presence of Russia and China on the UNSC, and their veto, resolutions are not easy to obtain.

And once an ultimatum had been issued there was a stark choice -- back up the threat with action or concede that the UNSC was just a talking shop. That would undermine the UN's broader authority and credibility.

Right up until the invasion Saddam had the chance to show his hand, to open his labs and weapons stores. He refused to and the weapons inspectors believed that he had something substantial to hide.

The war had another consequence: The preservation of Kurdish democracy. The Parliament of the Kurdish Autonomous Region had been established after the Kuwait War and maintained under the permanent protection of the US and the UK and the "no fly" zone they enforced.

The democracy of the Kurds has been a longstanding benefit to their people and a standing rebuke to those who would argue that Islam and democracy don't mix.

And let us not forget that with the establishment of a functioning democracy in Iraq the number of democracies in the Middle East doubled. Just Iraq and Israel. This too has been an unalloyed good.

What though about the "realpolitik" counterfactual?

Well, we could anticipate that Kurdish democracy would have been crushed by Saddam eventually. A government that would not back the UN would soon find a way to walk away from the Kurds.

A price worth paying for stability? For some perhaps, but this fantasy of a peaceful Middle East if we had not intervened in Iraq is just that -- a fantasy. Had Saddam survived in 2003, he would not have survived long-term because of the Arab Spring.

That is the source and wellspring of the discontent in Syria, and has seen a brutal dictator gassing and barrel-bombing his own people. The result? The displacement of 10m Syrians, half the population, and a refugee crisis that is overwhelming Turkey and the European Union.

The forces that tore apart Egypt and are tearing apart Syria would have torn Saddam's Iraq apart had it been allowed to survive.

Iraq, Libya, Syria. There are no easy answers. But there is doing the right thing, which we did when we liberated Iraq. And that remains a matter for celebration.

Comment by John McTernan, a writer, thinker, and political strategist. He has advised world leaders including Tony Blair and Australian prime minister Julia Gillard. You can follow him on Twitter at @johnmcternan.