Roh said his country "is not taking part in the full scope" of the security initiative, but that it would "support the principles and goals " and would cooperate in preventing the transfer of material for weapons of mass destruction.
Bush met with Roh before the opening of a Vietnam summit of 21 Pacific Rim leaders. Bush tried to put the best face on the disagreement, saying he and Roh have a mutual desire to "effectively enforce the will of the world" through UN sanctions imposed on North Korea for its nuclear test.
"I appreciate the cooperation we're receiving from South Korea for the Proliferation Security Initiative . . . Our desire is to solve the North Korean issue peacefully," Bush said.
"We want the North Korean leaders to hear that if it gives up its weapons -- nuclear weapons ambitions -- that we would be willing to enter into security arrangements with the North Koreans, as well as move forward new economic incentives for the North Korean people," he said.
North Korea is a primary target of the Proliferation Security Initiative. South Korea has been only an observer to the program out of concern its direct participation in stopping and searching North Korean ships could lead to armed clashes with its volatile neighbor.
The White House acknowledged that Roh faced political pressure not to anger North Korea. Bush "understands political constraints," White House press secretary Tony Snow said.
Bush was the second US president to visit Vietnam since the war ended three decades ago with US defeat. In Hanoi, powerful reminders remain of the fighting three decades ago, the longest US war and one that -- like Iraq -- deeply divided Americans.
Asked whether the experience in Vietnam offered lessons for Iraq, Bush said, "We tend to want there to be instant success in the world, and the task in Iraq is going to take a while."
He said "it's just going to take a long period " for "an ideology of freedom to overcome an ideology of hate. Yet, the world that we live in today is one where they want things to happen immediately."
In weekend discussions, Bush hoped to coordinate strategy with China, Russia, Japan, and South Korea for the resumption of disarmament negotiations with North Korea.
