Around, around the sun we go: The moon goes round the earth. We do not die of death: We die of vertigo.
—Archibald MacLeish
The "mad momentum" of the nuclear-arms race, as former Defense Secretary Robert McNamara once described it, lost a bit of velocity last week—after a vertiginous go-around between the world's two superpowers. First, the U.S. Senate voted to begin work on the nation's projected Sentinel anti-ballistic missile (ABM) system, designed to provide a "thin" defense screen against enemy rockets. Barely 72 hours later, the Soviet Union called for talks on...