Only 38 percent of Americans believe that the Iraq War was "worth it." My own anecdotal, nonscientific survey of Washington-based foreign policy and national security professionals would put that number even lower, with an overwhelmingly majority of that small circle considering the 2003 invasion in particular to have been, as then-Washington Post correspondent Tom Ricks termed it in the title of his 2006 book, a "Fiasco."

On the 10th anniversary of the start of the Iraq war, much of the retrospection and lesson-learning has focused on how and why the United States came to lead the invasion. Was it a function of shoddy intelligence? Of a mistaken, and potentially ideologically driven, misunderstanding of the Middle East? Of cynical leadership?

But there's a second set of questions about the U.S.-led "fiasco" in Iraq: To what extent was it a disaster not just because of the decision to invade, but because of the way that invasion was executed?