For the second time in less than a year, former British prime minister Tony Blair testified before the Iraq Inquiry today. The Inquiry is investigating the circumstances that led up to the Iraq war and its aftermath. For the second time, Blair warned of collusion between Iran and al Qaeda.

Blair said that the problems post-Saddam Iraq faced would have been manageable had it not been for the nefarious influence of external actors such al Qaeda and Iran. No one foresaw their collusion on the eve of the Iraq war, Blair testified. But al Qaeda’s spectacular suicide bombings and Iran’s extensive sponsorship of terrorists and extremists were the main drivers of the violence that engulfed Iraq in violence.

Towards the end of his testimony, Blair described the two biggest lessons he learned from the Iraq War. He began by saying that “one of those lessons has to do with the link between AQ and Iran.” Blair added (emphasis added):

I wanted to make it very clear to you that I think you need to look at this issue to do with AQ and Iran in a broader context and also the linkages between the two, because I think there are a whole series of, particularly, defense intelligence reports from 2005 and 2006 which are very, very important in this regard and which detail quite extensively the nature of those activities.

Earlier in the day, Blair also told the Inquiry that he did not think the West could deal with al Qaeda without dealing with Iran.

Blair addressed the relationship between Iran and al Qaeda in his written testimony submitted to the Inquiry as well. In a section entitled, “The Role of AQ and Iran,” Blair explains that the British intelligence community drastically underestimated both al Qaeda’s and Iran’s designs on post-Saddam Iraq. Their roles were a “game-changer,” Blair contends, and “the dimension not foreseen, that almost tipped Iraq into the abyss.”

“If anything,” Blair writes, “it was thought that whilst Iran would have a keen interest, naturally, in what happened in Iraq it would be more interested in promoting stability than instability.”

That was clearly wrong, Blair says. And that assessment quickly changed after the March 2003 invasion, when intelligence reports highlighting Iranian sponsored violence began to pour in.

One such British report, dated September 23, 2004, “stated that the Sunni extremist presence in Iran was ‘substantial.’” Blair adds: “This was emphasised in December 2004.”

Blair told the Inquiry that British intelligence officials were more concerned about the possibility of al Qaeda attacks inside the UK and elsewhere than they were about the al Qaeda network already operating inside Iraq. And this was a serious shortcoming in their pre-war analyses.

In his written testimony, Blair explains:

There was no sense that AQ would mount a full-scale operation in Iraq after the removal of Saddam. In retrospect as I said in my evidence, the intelligence that al-Zarqawi, the Jordanian AQ leader, had been in Baghdad in May 2002 should perhaps have been given more weight. But actually most of the British authorities were at pains to separate Saddam from AQ in 2002 not to link them.

That changed after the war had begun, however, and the roles played by both al Qaeda and Iran became “obvious.” Blair writes:

Throughout 2003-2007 I would be chairing meetings, receiving updates, getting weekly reports on the situation all of which reflected this changing security picture. In any event, the roles of AQ and Iran became increasingly obvious and open. AQ was claiming responsibility for the terrorist attacks and the U.S. and our special forces were focussed on going after them. The type and nature of the EFP and IEDs made Iranian involvement clear. This was backed up by the intelligence. Muqtada Al Sadr, whose JAM militia was our main opponent at the time, fled to Iran.

There is a temptation throughout the West to think of Iran and al Qaeda as separate problems. But Blair has repeatedly rejected that notion. In his testimony before the Inquiry last year, Blair explained:

What nobody foresaw was that Iran would actually end up supporting AQ. The conventional wisdom was these two are completely different types of people because Iran is Shia, the Al-Qaeda people are Sunni and therefore, you know, the two would never mix. What happened in the end was that they did because they both had a common interest in destabilising the country, and for Iran I think the reason they were interested in destabilising Iraq was because they worried about having a functioning majority Shia country with a democracy on their doorstep, and for Al-Qaeda they knew perfectly well their whole mission was to try and say the West was oppressing Islam. It is hard to do that if you replace tyrannical governments with functioning democracies.

Many in the West still do not understand this today.

Thomas Joscelyn is a senior fellow at the Foundation for Defense of Democracies.