There is a question about the U.S.-led invasion of Iraq that, 20 years later, remains a matter of deep uncertainty and debate among historians, political scientists and even officials who helped set the war in motion.
It’s not the war’s toll in American military deaths (about 4,600) or Iraqi lives (estimates generally fall around 300,000 or more killed directly by fighting). Nor the financial cost to the United States ($815 billion, not counting indirect costs like lost productivity).