I see that region has seen turning points in just the past 20 years.
1. Invasion was favored over containment. The policy after the Persian Gulf War was to enforce no fly zones to protect the Kurds in the north and Shia in the south and west and contain Hussein from invading anywhere else. Until we abandoned this in 2002. Had this containment policy remained, the situation there would most likely be completely different today.
https://www.nytimes.com/2003/02/02/opinion/keeping-saddam-hussein-in-a-box.html
1b. Putin was originally supportive of the war in Afghanistan. He even let us use Russian airfields. It was believed at the time that we’d join forces to fight radical Islam worldwide. It was widely known that he saw the Iraqi war as an intrusion into his sphere of influence and the beginning of our sour relationship. Who knows what our relations would be like today between us and Russia had we never invaded? Putin might still have blamed us for embarrassing election results or poor economics. Who knows?
2. The invasion was one thing. The rebuild was another. Disbanding iraq’s Military and reorganizing the police force disenfranchised thousands of Sunnis/members of Hussein’s party which created the insurgency against the new government. Had Sunnis/Baathists remained more involved, the insurgency might never have risen. Zarqawi wouldn’t have found soldiers to fight his jihad.
Meanwhile, the rebuild was disorganized and poorly run. We used Hussein’s palaces, making us look as imperialists. We had incompetent cronies in charge of the rebuild. It was a disaster.
https://time.com/3900753/isis-iraq-syria-army-united-states-military/
3. Abu Gharib was a real turning point. Humiliating Muslim men was one of the greatest gifts we have to Zarqawi’s recruitment efforts.
https://www.aljazeera.com/indepth/opinion/abu-ghraib-legacy-torture-war-terror-170928154012053.html
4. Pulling out of Iraq too early. This was a no winner for Obama politically. Liberal Democrats would’ve attacked him had he stayed and republicans wouldn’t have given him any credit. In hindsight, we pulled out way too early.
5. Arab Spring and the world’s reaction to it. Our reaction has been too slow. Assad poured gasoline onto the fire. Had Assad reacted in a more measured manner he could’ve diffused the situation. His own citizens (many of which are sunni Baathist. Assad is Shia)were demanding modest economic and social reforms. He overreacted and his actions created the bloodbath in that region.
https://www.theguardian.com/commentisfree/2011/may/18/syria-uprising-reform-bashar-al-assad
https://www.pri.org/stories/2011-04-23/syria-how-it-all-began