Zelizer : Some Vietnam-Afghanistan comparisons have merit . Comment: In Afghanistan , the U.S. is dealing with a war front that is notoriously treacherous , as the Soviets learned in the 1980s and the U.S. has learned since 2001 . Zelizer : Obama should use lessons of Vietnam as a guide .
Zelizer : Some Vietnam-Afghanistan comparisons have merit . Comment: Zelizer : Obama should use lessons of Vietnam as a guide .