The meaning of pre-emption, as defined by the George W. Bush administration, is simple: Strike your enemy before he strikes you.
With its pre-emptive strike against Iraq two months ago, the US was spared a Saddam Hussein-sponsored terrorist attack, or so the administration believes.
But South Korean President Roh Moo-hyun is steadfastly opposed to a US pre-emptive strike as a way of dealing with his country's troublesome neighbor, North Korea.
And Roh says he would so inform US President George W. Bush when the two sat down together yesterday evening at the White House for their first meeting.
"The mere thought of a military conflict with North Korea is a calamity for us," Roh said in a recent interview with The Washington Times.
The South Korean leader, in office less than three months, believes that continued engagement with the North is the best policy, and Bush, for all his concerns about the North's menacing military buildup, is expected to concur at their meeting.
Bush has said all along he favors a diplomatic solution, while emphasizing that no option is being ruled out.
But Roh is not sure how long Bush is prepared to stick with his policy of patient diplomacy. He is aware that many in the administration believe that engagement with North Korea is a fruitless exercise.
"There are some Koreans who believe that President Bush's peaceful resolution principles may change at any minute," he says.
As Roh's statement suggests, the problem of how to deal with North Korea has created a certain wariness in US-South Korean relations.
Americans were taken aback last fall when tens of thousands of South Koreans took to the streets after the disclosure that North Korea was developing uranium-based nuclear weapons.
The demonstrations were not directed at Pyongyang so much as they were at American hostility toward North Korea. Not long thereafter, Roh was elected on a peace platform.
The Bush administration understands South Korea's concerns, recognizing that North Korea is capable of mass slaughter across the border at a moment's notice, with perhaps hundreds of thousands dead in the first week.
As Roh sees it, the answer is not saber rattling but dialogue, a point he stressed on Tuesday at a US Chamber of Commerce luncheon.
"Trust will be established among parties, and the door to peaceful resolution will open if the parties involved engage in dialogue with sincerity," said Roh.
Some in the administration doubt that mere dialogue will induce the North Koreans to dismantle their nuclear weapons and their missile programs. In some quarters, Roh is regarded as a toothless appeaser.
Without credible pressure, Roh's critics in the administration believe that North Korea will simply proliferate on a greater scale than before, marketing nuclear weapons to the highest bidder -- much as they have with missiles.
Administration statements over the past two years have reflected confusion. They have fluctuated between mudslinging (Bush's speech placing North Korea in an "axis of evil" with Iraq and Iran) and a yearning for engagement.
And if the North Koreans agree to dismantle their nuclear weapons program, can they be counted on to comply?
James Lilley, a former US ambassador to South Korea and China, is not optimistic. "Foreign contrivances, such as roadmaps, frameworks, armistice treaties, in the North Korean view, are to be circumvented and undermined," he says. "North Koreans see them as devices to lock in foreigners but not to restrict North Korean behavior or actions."