Conservatives like to trot out the example of the USSR when they say that communism doesn’t work. They laugh at the whiners who say that it was the execution, not the idea, that failed.
Strangely enough, the simple example of Iraq doesn’t similarly discredit neoconservatism. They blame the execution of the war, even though it was flawed from the beginning.
Neoconservatives would use a hammer to conduct surgery and when the patient dies, they’d complain that the doctor didn’t hit hard enough.