WASHINGTON (AP) -- President Bush's recent acknowledgment that the war in Iraq was comparable to the Viet Cong's psychologically devastating Tet Offensive in 1968 was hardly the first time a parallel has been drawn between the Iraq and Vietnam conflicts.

Questions about a "quagmire" have haunted the president's Iraq policy since before a single bomb fell on Baghdad. But this week, amid an intensifying discussion at home about the future of the war, Bush gives the comparison debate another kick by walking among Vietnam War relics on a four-day visit to the communist nation created after American troops departed 33 years ago.

The president left the White House on Tuesday night, planning to stop briefly in Moscow and then in Singapore before arriving in Hanoi on Friday for a state visit and a massive summit of Pacific Rim leaders. He also spends a day in Ho Chi Minh City, formerly Saigon.