The More Presidential, the Better

But there is uncertainty about what those standards are. Because performance is so much a part of politics, because television has become so much a campaign vehicle, and because Mr. Reagan has made performance before the camera so integral to his Presidency, the assumptions about what is Presidential, what is political and what is hype remain clouded.

Each of the previous two Presidents, Jimmy Carter and Gerald R. Ford, had all the advantages of incumbency that Mr. Reagan is using so well. Their challengers in 1976 and 1980 complained, accurately enough, that Mr. Ford and then Mr. Carter got on television with trivial, staged events because of their office.

''But they couldn't seem Presidential,'' says Paul Greenberg, executive producer of ''The NBC Nightly News.'' ''This man seems Presidential. You have to be careful how you report him, because maybe he is Presidential.''

And that, perhaps, is the import of the carefully developed Reagan television presence: He has made the aura, the act of seeming Presidential a credential instead of a posture.

''You see, the whole thing is that we're not theater critics,'' says Joanne Moring, vice president of affiliate news services for NBC. ''We're covering the news.'' Reporting a President's Visit

The theatrical effectiveness of the Reagan presence begins with the trappings of the Presidency, which are powerfully dramatic. And they are most compelling in cities and towns where the local reporters are not accustomed to covering the President of the United States. It offers a dramatic appeal Mr. Mondale cannot begin to match.

Furthermore, the reporters on the scene are not as likely as the national press to know whether what Mr. Reagan says or does is new. ''Everything he says is reported by our affiliates as if it's freshly printed on the book of life,'' Miss Moring says. Packaging of Patriotism