Even the Russians agree that Senator Kennedy is wrong to compare Iraq to Vietnam! Here is a money quote:
It was Kennedy's older brother, John F. Kennedy, who dragged the United States into the Vietnam quagmire, and the senator should know better than to compare Vietnam and Iraq.
The Vietnam War was a battlefield in the global Cold War that pitted the United States against the Soviet Union and its allies. The Soviet defense industry supplied the North Vietnamese with the latest weapons. In 1975 North Vietnamese regulars, armed and trained by the Soviets, took Saigon. "Winning" the war in Vietnam was impossible without first winning the Cold War. So long as the Soviets were able to maintain a global balance of power, any local war -- in Vietnam, Afghanistan, Nicaragua -- tended to develop into a quagmire.
A tip of the hat to Glenn Reynolds for this link.