First, intelligence can underestimate as well as overestimate a threat. UN inspectors in 1991 were stunned how close Iraq was to producing nuclear weapons before its programme was dismantled. Remember Eisenhower’s famous contingency note in case the D-Day invasion failed: “My decision to attack at this time and place was based upon the best information available.”

Second, as America’s Silberman-Robb Commission stressed (in March, 2005, no less), the critical error regarding chemical weapons was believing Saddam’s post-1991 declarations of extensive stockpiles. Iraq resisted repeated UN efforts to verify its claim of destroying its chemical weapons, leading everyone, from Hans Blix to Tony Blair to conclude in 2003 the opposite. In fact, Saddam lied about his capabilities and about trashing them. Had he stayed in power, he would today have even larger chemical stockpiles. His “nuclear mujahideen,” the 3,000 scientists and technicians he had retained, would have recreated his nuclear-weapons programme.

Since Chilcot will tediously prove yet again that hindsight is 20:20, let me strike pre-emptively: we should not have invaded Iraq in 2003. Instead, we should have finished the job in 1991 after ridding Kuwait of Iraqi aggressors. We were told then that Arab coalition members, especially Syria’s Assad dictatorship, would object to overthrowing Saddam. Perhaps they were seriously worried they were next. Too bad they weren’t. And there would have been no question of any Iraqi WMD after 1991.