WASHINGTON First came the pre-emptive military policy. Now comes the pre-emptive campaign strategy. Before the president even knows his opponent, his first political ad is blanketing Iowa today. "It would take one vial, one canister, one crate slipped into this country to bring a day of horror like none we have ever known," Mr. Bush says, in a State of the Union clip. Well, that's a comforting message from our commander in chief. Do we really need his cold, clammy hand on our spine at a time when we're already rattled by fresh terror threats at home and abroad? When...