Much of President Bush's case for ousting Saddam Hussein rests on the Iraqi leader's history of invasions, evasions, and actual use of chemical weapons.
But a weak part of the Bush argument relies on his reading of Mr. Hussein's intentions for the future that he'll do more of the same, or quickly build a nuclear weapon and pass it to terrorists or use it himself.
"To assume this regime's good faith is to bet the lives of millions and the peace of the world in a reckless gamble," Bush told the UN on Sept. 12. Past is prologue, Mr. Bush would argue.
Naysayers to Bush say war cannot be justified until there's proof of Hussein's game plan. And just finding a secret Iraqi nuclear-weapons program is not a smoking gun for a crime that's not been committed. That would be like the movie "Minority Report," in which psychics identify a future criminal before the crime.
That argument is worth considering simply because, if war does come, a question likely to be asked for years is whether the US correctly read one man's thinking.
It wouldn't be the first time a historic question about a war's correctness rested on interpretation of hidden thoughts. Just bring up Vietnam to older Americans, and opinions will fly over whether Ho Chi Minh was an agent of communism expansion or a patriot liberating and reunifying his country.
Ho was a complex leader, well versed in American principles, Marxist ideology, and Leninist tactics of trickery. Always a pragmatist, he could have just been using communism as a temporary tool to rid Vietnam of foreign influence. But then, he and his Politburo ran North Vietnam almost as ruthlessly as Mao did China, and did order an invasion of South Vietnam. Ho died in 1969, six years before the war ended, still a mystery to many.
As war with Iraq reaches a tipping point, a key lesson from past wars is the need to size up an enemy's motives carefully and make sure most Americans agree with the assessment.
Otherwise, a political war lives on long after the shooting war is over.