resident Bush, visiting a country that forced the United States into a humiliating withdrawal three decades ago, declared Friday that Vietnam’s transition to a modern, growing economy gave him hope about what could be rebuilt from the ruins of Iraq. But he added that the lesson he drew from the bitter American experience here was that “we’ll succeed unless we quit.”...

Carefully avoiding any direct mention of how the Vietnam War ended for the United States, Mr. Bush instead focused on the deepening — if still wary — economic and diplomatic ties between the two countries.

“History has a long march to it,” Mr. Bush said in response to a question about how he felt about arriving here, the second American president to visit since the war’s end. “Societies change and relationships can constantly be altered to the good.”...

But it was the Iraq comparisons that were the most difficult, because they required Mr. Bush to argue two seemingly contradictory threads: that Vietnam turned out well despite America’s withdrawal, but that the situation in Iraq was so much more complicated that retreat was not an option.

“The Maliki government is going to make it unless the coalition leaves before they have a chance to make it,” he said of Iraq’s prime minister, Nuri Kamal al-Maliki.