LONDON -- "I will not wait on events while dangers gather." Thus speaks U.S. President George W. Bush -- and in doing so appears to state, in plain and simple language, a revolutionary new doctrine that upends five decades of thinking about global security.

For what the president is saying -- and it sounds quite reasonable after the terrible events of Sept. 11 -- is that the United States will strike first. It will never again wait passively to be attacked and then hit back. That would be too late, as it was too late for the thousands who died that fateful day in New York.

But strike first with what and at what? If the president is saying that America will ruthlessly hunt down terrorists and search out their training camps, wherever in the world they may be, with agile new super-mobile forces, that is not a new intention. If he is saying that America's vast conventional forces will be launched against regimes that harbor and succor terrorism of the al-Qaeda variety, that, too, sounds familiar and predictable, even if it raises severe logistic problems (how, for example, do you march on Baghdad without unacceptable casualties all round?).