Part 4. Ken Burns is working on a Vietnam documentary slated for a few TV seasons from now, and the PBS Vietnam: A Television History series did an excellent job on the same topic way, way back in 1983. But in between the past and the future of TV Vietnam documentaries, CNN’s The Sixties gives us this present: a new installment called The War in Vietnam, which looks at how America, and Americans, responded to being increasingly embroiled in a war that seemed both unwinnable and, in some ways, unacceptable. Sound familiar?