Book excerpt: An authoritative military history of the U.S. Army's 3rd Infantry Division in Operation Iraqi Freedom, describing the 2003 invasion of Iraq, the siege and fall of Baghdad, and the nation-building mission that followed. In 21 Days to Baghdad, historian Dr. Heather Stur describes the commitment of the division to Kuwait, the invasion of Iraq and the three weeks of violent desert conflicts on the way to Baghdad before the siege and battle for the city itself, and the “thunder runs” that saw its fall to U.S. forces. She then details the complex security mission that required the soldiers and their commanders to convince Iraqi citizens that the U.S. was there to help them, while at the same time they continued fighting Saddam Hussein's elite Republican Guard, paramilitary forces, and terrorists. This new history is based on exclusive, extensive interviews with General Buford “Buff” Blount, the U.S. Army two-star general who led the 3rd Infantry Division. His years of experience in the Middle East led him to question the recall of his division from Iraq at the end of 2003 and its replacement by a less experienced unit. President George W. Bush and Secretary of Defense Donald Rumsfeld did not believe that peacekeeping and humanitarian assistance were worthwhile uses of a conventional combat force like the 3rd Infantry Division. The division had destroyed Hussein's government. Mission accomplished, or so Bush and Rumsfeld thought. 21 Days to Baghdad illustrates the long reach of the U.S. military, the limitations of nation building in the wake of war, and the tensions between policymakers in Washington, DC, and troops on the ground over the purpose and conduct of the U.S. invasion of Iraq.