POLITICS: McGovern Moves Front, Maybe Center

LAS VEGAS Oddsmaker Jimmy the Greek last January figured him a 50-to-1 shot to be nominated President. Only three months ago, national polls rated him 5% in any Democratic field. In the corridors of the Senate Office Building last winter, like the Ancient Mariner he would stop reporters and ask plaintively: "Why aren't you covering me? I'm a serious candidate!"

Last week it became precisely clear how serious South Dakota's George McGovern is. With a certain cool relentlessness, he swept another four primaries—New Jersey, New Mexico, South Dakota and, most crucially, the...