"In 1973, the Vietnam War ended in a cease-fire and a U.S. withdrawal that included promises by President Nixon to assist the South in the event of invasion by the North. But in early 1975, when North Vietnamese forces began to attack, Congress refused to send arms or aid. By April 5, the South was on the brink of defeat, spelling execution or years in a concentration camp for the untold number of South Vietnamese who had supported the government...