"BRING US TOGETHER" - it used to be a Nixon administration motto of sorts, but Jimmy Carter has given it life. However much the president may have done in the past two weeks to corner the malaise vote, you have to concede that he has also done wonders in uniting his party. When George McGovern, the Demorcrat from the state of Disarmament and Henry Jackson, scourge of SALT I and II, reveal within a day of each other their common hospitality to a Teddy Kennedy candidacy that would displace the incumbent Mr. Carter...well, it bespeaks a condition of harmony within the Democratic Party that is unprecedented in modern times. It is true that Sen. Jackson didn't exactly disavow Mr. Carter for Mr. Kennedy - but he came awfully close. All that remains now to heal the divisions that became so deeply geologic back in 1972 is for a repentant John Connally to return. Maybe Mr. McGovern will give the speech at the 1980 convention, with all the resonances that would entail: Come home, John Connally.

What does it all mean? Our own considered and carefully weighed response is, almost nothing. Yes, it is true that the many-parted surge for a Kennedy candidacy says something - and something not very reassuring from the White House's point of view - about the grip of Mr. Carter on the loyalty of a broad range of party opinion. But there is time for him to do something about that, if he can. And the real point is that it doesn't say anything very reassuring about the prospects of a Kennedy candidacy either. So long as the Massachusetts senator is able to keep up his at-the-edge dalliance with his party's presidential nomination, he will probably be able to maintain his imporbable coalition - based as it is on reaction, disappointment with the present officeholder and vague yearning, as distinct from loyalty to program and position.

Actually, a candidate (viz., Mr. Carter himself as well as Sen. McGovern) can sometimes keep this odd-couple kind of support going through the primaries and even for a time after the nomination. But sooner or later some choices have to be made, a program with at least a modicum of inner coherence and practicality has to be adopted. And this exercise invariably jars and alienates some part of the constituency whose early sympathy was so helpful.

It may be true that on an issue like SALT II, for absolutely different reasons, two men as absolutely different as George McGovern and Henry Jackson can find themselves united in opposition. But Sen. Kennedy knows that this is not the sort of thing political coalitions and triumphs are made of. We suspect he also knows that these two friendly signals from the past week say something quite different from, even opposite to, what they seem to suggest at first glance. They say that the political party Sen. Kennedy would have to lead, if he were to get the nomination, is the same old unwieldy, polarized and hard-to-control bunch it always was; that it stretches all the way from Mr. McGovern to Mr. Jackson, and that a Kennedy candidacy - once deprived of the diverting and insulating glamor of the will he/won't he question - would be as likely as any other to bog down in the morass.