Gray clouds sweep over the mountains around Blantyre, Malawi, bringing raindrops that tap at the windows of the men's ward in Queen Elizabeth Hospital. Inside, a young man sheepishly removes his shirt as a doctor and two medical students arrive at his bed. A brief exam reveals thrush, shingles, and wasting, and the med students diagnose a classic case of HIV. The doctor, Claire Scarborough, nods in agreement. Later, she estimates that 80 percent of the patients are HIV-positive. Many of them look young.

George W. Bush's decision to unilaterally invade Iraq in March 2003 has placed a severe strain on the US military. The Army currently has almost half of its 32 combat brigades deployed there, with two more assigned to Afghanistan. This means that three-quarters of its forces are either committed to combat zones or recuperating from recent combat.