The FACT is: neither you nor I know if our actions in Iraq prevented a specific attack. However, the odds are on my side.
The simple fact is that this war in Iraq had absolutely nothing to do with WMD, we were lied to about that, and indeed the entire debacle has been only a distraction as truly scary places like North Korea and Iran moved on with their programs.
That is a direct lie on your part. This war started with the consent of the UN, Congress and nearly every commentator available. All were given access to the intelligence. All acknowledged Iraq's past use and pursuit of WMD's. All agreed that Sadaam did not comply with post-war agreements.
Now you want to call it a lie. You have no facts to offer.
You miss the fundamental point that they're not Americans, and so we owe them no duty. Leave them to their fate.
That thinking is what caused World War 2 after World War 1. We left a broken, destroyed region to the machinations of dictators until those dictators nearly overpowered the entire world.