I hate the word "blowback" -- it's ideological 'Ratspeak/Commiespeak </off redundancy mode>, and their slanguage is the enemy of clear thought.
"Entailed consequences" and "ramifications" are what conservatives talk about, and there was plenty of talk in 2003, when George Bush succumbed to the mission-creep advocacy of the national-greatness Republicans (John McCain, exhibit A) and the neoconservatives in the administration (Wolfowitz, Richard Perle, Richard Cheney et al.).
There were lots of conservatives in 2003 who advocated "in-and-out": Kill Saddam, kill the "wolf cubs" to destroy regime continuity, break down the regime, break his Republican Guards, and go home. Remember that it was Colin Powell who invoked the "Pottery Barn rule"; his was a minority report, cold rissoles from the 41 administration about a "viable Iraq", that became Bush Administration policy. By contrast, Stephen Decatur and his president, Thomas Jefferson, hallucinated no such obligation toward the corsairs of the Maghreb, and would not have agreed with Powell on the subject of "nation-building".
As for your comment about "no question", George Bush did master the Iranians' Badr Brigade tools and AQI and left Jug Ears a pacified Iraq, which Jug Ears promptly threw away with his self-consequent ideological pronunciamentos that by themselves made everything instantly worse, and then deepened the dissolution of America's gains by simply bugging out and leaving Iraq to become a pawn of Iran and a sectarian battlefield. Bush mastered the bad guys, and Obama sympathized with and fomented them, it's as simple as that.
The nature of terrorism is ebb and flow[war of the flea], Iraq was not pacified, but merely part of training regime for terrorists. After the downfall of strongmen, especially in shia/sunni fault lines, the obvious repercussions were gonna happen. ISIS and such Sunni actors are merely carrying out what they have always done. This is simply demographics sped up and televised.
Mrs. Clinton faces no questions about here effort to take out Qaddaffi and the campaign to even destabilized Libya even more. And like Iraq, we are dealing with such ripples.