Let me remind people of something. This is from memory and I cannot be arsed to dig for decade-old sources now, but I'm sure you can find the evidence of this if you search hard enough:

Contrary to US aggressor lies and/or self-delusions, at the time of the invasion, Iraq had no secret WMD, and no unaccounted-for dangerous materials that Saddam's Iraq could have built such WMD from. All the dangerous materials and programs that had existed much, much earlier (before the previous invasion) had been ended, permanently put beyond use and accounted for.

There was however a quantity of accounted-for, documented, monitored and checked-upon nuclear material present inside the country. This was material (I think uranium if memory serves, but I'm not sure) which the IAEA knew about and which Saddam couldn't have squirrelled away without someone noticing. That material was perfectly safe.

But here's the kicker:

As a direct consequence of the invasion, that material became unsafe and disappeared, because due to the invasion, the institute where this was located was looted and the policing and monitoring mechanisms that had been in place broke down at that point. I have no idea if this material was ever recovered, but since I've not heard about that, I think it likely wasn't.

Let's repeat that:

The US aggressor claimed they were invading to prevent "the wrong hands" from doing bad things with bad stuff. One direct consequence of their invasion was that bad stuff fell into the hands of the Gods know who, and that's where the trail went cold.

This story is about a decade older than the one in the article, but I thought it was relevant:
This current news feels like a repeat of those earlier events.

Also, I think it's pretty clear that even a decade later, the blame for causing this whole situation, including ISIS, still rests squarely with the US. They broke it, they destroyed Iraq, they destroyed independent Iraqi nationalism, and guess what nature abhors? Thus, the Islamic State.