General Giap started his big offensive on January 21, 1968, against the Americans at Khe Sanh, a Marine base just south of the DMZ near the Laotian border. Giap chose to attack right before Tet, a major Vietnamese holiday. In the past, both sides had traditionally observed a cease-fire during the festival, and Giap knew that half the South Vietnamese soldiers and many American troops would be on leave from their duties. Khe Sanh was not the main objective during the offensive, however; the purpose of the assault by thirtyfive thousand North Vietnamese soldiers was to distract the Americans from the buildup of NVA and VC forces that were preparing to attack other major cities and towns throughout South Vietnam. Ho and Giap were planning a grand revolt against the south called "General Offensive, General Uprising." The theory was that the South...