Bush couldn't find Bin Laden, and the military industrial complex needed $$$, so the WMD predicate was used to throw us into a middle east quagmire for going on 20 years (hint - we're still pulling triggers in Iraq and Syria to this day). WMD, "War on Terror", "Support Our Troops", "Fight them over there, not over here" - all are tropes used to incite support for a really stupid war.
Full Disclosure - I personally supported it at the time. That was for the first 5-6 years. But we beat the Japanese and the Nazis in 4 years. Once we passed that mark, reality set in - we're not playing to win. Ten years in, I started asking "who benefits?" Now almost twenty years in, only a fool would not see the grim truth that money and power in the region (pipelines, oil fields, etc.) drives everything and our men and women in the military are ground up and spit out for no other reason than that.
Don't be a fool...
Our beef with Saddam was legitimate, by signed cease-fire accord. Getting Bin Laden was a reasonable issue, too, as he was responsible for the Twin Towers attack.
Things beyond capturing either man and killing as many easily found bad people is bordering into either “nation-building” or “leadership vacuum remodeling,” which people on both sides said was better than to immediately leave.