Speaking as a former Bush supporter:
If Saddam were still in power, the Middle East would be slightly more stable. Like Rupert says, many our soldiers and those of our allies, would be alive and many more not disabled. Thousands of Iraqs would be alive as well, albeit still living tyranny.
There would be no ISIS. Middle Eastern strongmen were always able to clamp down on their religious nuts with their own style of domestic terror. Same goes for Libya. The Arab Spring brought us democracy in Egypt. How did that turn out? Not ready for primetime.
Also, it would have meant more resources for Afghanistan. That's where the real issue was and still exists. I truly believe the situation there would be quite different had we not invaded Iraq.
I have to wonder how someone could become President of the United States with such little conceptual knowledge of the world. How can you be fooled so easily by your VP, Def. Sec and CIA director? As a Republican for nearly 30 years, I'm disgusted. The damage to our reputation will take years to rebuild. I'm all for spreading freedom, but not at the expense of weakening our own position in the world. You can support movements inside countries like we did in the last century.
Oddly though, W is still well respected among the troops. He visits VA hospitals as well as bases regularly and is warmly received. I would be very angry.