PRESIDENT CARTER gave himself a ringing endorsement on Tuesday, one of the most enthusiastic he has yet received. Mr. Carter said to his audience: "You'll determine whether or not this America will be unified or, if I lose the election, whether Americans might be separated, black from white, Jew from Christian, North from South, rural from urban, whether this nation will be guided from a sense of long-range commitment to peace, sound judgment . . ." etc. etc. At first on reading this screed it occurred to us that it might be a devilishly clever maneuver to outsmart the Christian right. Why settle for the evangelicals, after all, when you can actually have the messiah? But no, it appears to have been something else.

To a reporter who inquired yesterday about the point of these remarks, especially their implication that Ronald Reagan is some kind of anti-Semite, Jody Powell responded that the remarks represented Mr. Carter's profound outrage that Ronald Reagan should have visited Rev. Jerry Falwell on the 3rd of October. There Mr. Reagan rejected Rev. Falwell's quaint insistence that he and some of the other clerical cognoscenti know exactly whose prayers God does and doesn't hear, but apparently he failed to do so with a force the president thought sufficient. This explanation would be more compelling if the president had not in fact made just about exactly the same statement (the election would determine whether there'll be an alienation of black from white or Christian from Jew or North from South or rural from urban") on Sept. 30 in Washington, three days before the event that is now said to have so outraged him. Perhaps this is preemptive outrage -- you experience it before the outraging event occurs, not just after.

We have yet to read a newspaper headline disclosing: Catholics Believe Jews Don't Go to Heaven, or, Moslems Believe Episcopalians Are Wasting Their Time, but there is still a month to go in this campaign, so neither possibility can be entirely ruled out. But the point of the ghastly exercise in Chicago the other day and in Washington before that is not that religion plus politics plus media intervention have combined to make a distinctly unholy mess of this election, which they have. It is that Jimmy Carter is campaigning like a politician gone haywire. Where is the president ? How can he keep making these frantic, overstated, boomeranging attacks that invite, of all things, a serene-looking Ronald Reagan to put him down deftly and walk away with the political points. The Californian's response yesterday ("I can't be angry. I'm saddened that anyone . . . who has had that position could intimate such a thing. . .") comes to us in precisely the voice and tone you would have thought the president would be taking by now with Mr. Reagan.

There is complaint from Jimmy Carter's White House that the media have not been dealing with the issues in this campaign. But it is not the press that has brought Mr. Carter to this pass. It is Mr. Carter. He's got the better of the argument, in our judgment, on some of the big ones.Why doesn't he start making the case and come off the demeaning (to him) assaults?