SUPER TUESDAY delivered. After the warm-up rounds of Iowa and New Hampshire, Tuesday's presidential primary and caucus events in 20 states provided the megatonnage to separate the leaders from the packs. George Bush's performance was the most impressive - nearly a clean sweep of the states. Yet it was not the number of states he carried alone that made his victory notable - it was the margin, approaching 3 to 1 across the South against Robert Dole. This was an unprecedented showing in seriously contested contests in a cluster of states.
We have argued before that Mr. Bush has always been ahead of his Republican rivals to replace Ronald Reagan as the GOP standard-bearer. His successorship was evident as long ago as 1980. Bush had been finished off by Mr. Reagan after a single debate in Nashua, N.H. But in a show of sheer persistence Bush endured through every state contest to the end in California - the vice-presidency his reward. He has paid his dues. His loyalty to Reagan certainly helped him in the South on Tuesday, a region where such personal traits count, and a region both sides need to carry to win in November.
Among the other Republicans, Mr. Dole may hope for a comeback in Illinois, his Midwest turf, or for a flare-up of bad publicity for Bush from the Iran-contra prosecutions, or some other break. He does not appear to want the vice-presidency. He contends that surveys show him running stronger than Bush against the known Democratic rivals. Perhaps a credible second place to Bush could set him up for a 1992 race, should Bush get beaten this fall. But Dole will have a hard time talking his way out of Tuesday's drubbing. And Pat Robertson and Jack Kemp were made to look like fringe candidates.
On the Democratic side, Michael Dukakis's margins were less impressive than Bush's. But when Albert Gore's success against Mr. Dukakis's prior chief rival, Richard Gephardt, is factored in, Dukakis's position was greatly enhanced Tuesday. He did well in Texas and Florida, the kind of swing states he would need to carry against Bush in November. It is hard now to see how Dukakis can be stopped from getting the nomination.
Mr. Gore's victories Tuesday were largely in the border states. The Deep South went to Jesse Jackson. The Rev. Mr. Jackson in some ways remains the most interesting presidential candidate in 1988. He tended to place second everywhere except where he won. Overall, he may have won the most Democratic votes. But there is no way to avoid confronting questions raised by the persistent refusal of whites - fewer than 1 in 10 in the primaries - to vote for Jackson. In a country 89 percent white, one has to ask whether it is Jackson's own weaknesses as a presidential figure, or an underlying racial view of white America, that must be overcome. If the former, Jackson must improve his appeal; if the latter, Americans must examine their hearts.
A last point: It is silly to maintain that Super Tuesday made it more likely that the Democrats would again nominate a liberal. When in recent years have they not nominated a liberal? The Democratic Party is today a liberal party, the GOP a conservative party, especially in the party-activist phase of the nominations. This is clearer when the parties are compared with 1960, when the Democrats had more of a conservative wing and the Republicans a moderate wing.
Whatever else can be said of Super Tuesday, it brought a lot of resolution to the races for the 1988 presidential nomination.