Why did the same intelligence community overestimate the threat of Hussein’s Iraq then underestimate the threat of ISIL?
Simple. They’re human. They tailored their findings to their perceived expectations of the then President. Neither Bush nor Obama (nor the public) should blame them for catering to their expectations when each made his preferences so clear.
Then how do we get better intelligence? Elect a chief executive with enough integrity that his staff will tell him the truth, rather than what they think he wants to hear.
No, I can’t name a modern President who did that. Maybe Truman or Eisenhower, if you accept them as modern. Certainly not JFK or Nixon. I really don’t think Reagan or Clinton.
Integrity is an endangered specie inside the Beltway, perhaps due to lack of safe habitat.