New Blair documents complicate the story of the Iraq War

Mr Blair, who left government in 2007, agonised over what the West should have done about Saddam Hussain. EPA

In the heady early days of Tony Blair's government, few British people would have guessed quite how controversial his legacy would be after he left office in 2007. The former prime minister did plenty of good for the UK and further afield. But he has been unable to shake anger for his role in one key tragedy, the 2003 Iraq War.

Context is particularly important when it comes to the conflict. We got more of it yesterday, when the UK released documents from inside government at the time.

Mr Blair is often criticised for going too hastily to war. An official British inquiry report into the invasion did indeed conclude that the campaign began “before the peaceful options for disarmament had been exhausted”.

But these new documents make it harder to claim that the government did not think seriously about the potential for major consequences. Instead, they show quite how much and for how long Mr Blair and his colleagues agonised over what to do about Saddam Hussein, Iraq's former president, who led one of the world's most destabilising regimes before he was toppled in 2003.

These revelations do not hide the fact that the events in western capitals leading up to the conflict were morally controversial. A famous example for Mr Blair is the "dodgy dossier", the nickname given to a flawed and inaccurate September 2002 document presented to the British parliament, which claimed Iraqi forces had the capability of launching weapons of mass destruction that could hit Western targets within 45 minutes.

And the architects of the conflict remain primarily responsible for its tragic aftermath. Many of Mr Blair's worries in the documents came true, such as it fuelling a rise in Islamist extremism and the legacy of its murky legal justifications.

The episode had another major global implication, the results of which we are seeing today. The failures, moral controversies and widespread condemnation throughout the war contributed to the end of an era in which Western nations had the confidence to intervene abroad in a full-blown, military sense, at least in traditional forms.

While it is good for major powers to understand the devastation they can cause if force is deployed inappropriately, today's trend of Western disengagement, seen most controversially as Nato leaves Afghanistan, risks spreading beyond the military sphere. Countries must not lose the confidence to engage peacefully through diplomacy and aid. If they stop doing so, strife in the region becomes more likely, not less.

It also makes the nature of modern warfare more ambiguous. Images in 2003 of Americans storming Baghdad in traditional military formations are a thing of the past. Nowadays, the trend is towards asymmetric tactics, which arguably make peace harder to secure.

Yesterday, ISIS claimed responsibility for a suicide bombing in Baghdad that, at the time of writing, has killed 35 people and wounded 60. The conditions that make these sorts of tragedies commonplace, such as a rise in terrorist groups and militias and a fractured state and security apparatus, are closely linked to Iraq's destabilising past, of which the 2003 invasion is a huge part.

The conflict is often over-simplified. These documents provide yet more evidence that the events leading up to it were, instead, complex. But however many new details we might learn in the future, the simple fact remains that for Iraqis, the tragedy of the past few decades is not over yet.