WHEN THE U.S. INVADED Iraq in March 2003, many economists feared that the war would lead to a sharp decline in Iraqi oil production, a spike in oil prices, and a woeful U.S. economy that would follow the scripts of the oil shocks of 1973, 1978, and 1990. Real oil prices did increase, indeed more than tripled, from $20 in 2001:Q4 to $62 in 2006:Q3 (in 2007 dollars). But the ailments associated w...