President Bush says he sees a possible parallel in the increase in violence in Iraq and the 1968 Tet offensive that prompted Americans to lose support for the Vietnam War.
Asked in an ABC Newsinterview last night whether he agreed with an opinion by New York Timescolumnist Thomas Friedman that the current violence in Iraq was "the jihadist equivalent of the Tet offensive," Mr Bush said: "He could be right."
"There's certainly a stepped-up level of violence, and we're heading into an election," Mr Bush said.
Republicans face the possibility of losing control of the Congress largely due to the unpopularity of the Iraq war.
Although communist forces lost the Tet offensive, it was a major propaganda victory and is widely considered a turning point of the war in Vietnam, prompting support for the conflict to deteriorate.
President Lyndon Johnson's popularity fell, and he withdrew as a candidate for re-election in March 1968.
"Look, here's how I view it," Mr Bush said of the situation in Iraq. "First of all, al-Qaeda is still very active in Iraq. They are dangerous. They are lethal. They are trying to not only kill American troops, but they're trying to foment sectarian violence.
"They believe that if they can create enough chaos, the American people will grow sick and tired of the Iraqi effort and will cause government to withdraw," he said.