Donald Rumsfeld provoked strong feelings. The two-time defense secretary was hailed by some as smart, tireless and politically cunning. Others saw him as responsible for a catastrophic war in Iraq and who remained unrepentant about his failings. Writer and journalist James Fallows interviewed Rumsfeld over the years, beginning in the early 1980s. Marco Werman speaks with him about who Rumsfeld was and what made him tick.