Somehow the Carter-briefing-papers flap still seems like a summertime, warm-weather incident that is destined gradually to fade away. There could, of course, be new developments that will necessitate a revision of that forecast.
There is no doubt that the whole affair is being fanned by Democrats desperate to find a hole in the President's strong political position. And no doubt, too, some in the news media are smacking their lips over the prospect of developing a Watergate-sized scandal.
This doesn't mean that use of confidential Democratic documents by the Reagan campaign people was excusable. An honorable course would have been for the Reaganites to send them back to the White House without even reading them. There has been precedent for that in the Mo Udall and Harry Truman camps.
For David Stockman to talk in an almost bragging way about having used those papers in preparing Reagan for the 1980 debate was deplorable. And if it should be proved that a high-up Reagan campaign aide actually was involved in the filching of these papers, then, of course, the incident takes on scandal proportions.
Obviously, the most damaging development would come if the President, a la Nixon, were found to have sanctioned or known about an invasion of Carter White House security in order to obtain these strategy papers. The Reagan White House is no longer taking ''Debategate'' lightly. But key Reagan aides are clearly frustrated over how to clear the air, now that the President's detailed responses to reporters' questions at the last press conference failed to deflate the story.
Reagan strategists make this assessment of ''Debategate'' and where it might lead:
* First, they believe the incident has taken on a life of itself that will not end suddenly but will have to play itself out, perhaps over the next several months. They blame the press for exaggerating the story and keeping it on front page.
* Second, they believe that the President is well positioned to withstand disclosures which raise questions about the ethical conduct of his administration and campaign - as long as it remains clear that he knew nothing about what went on and does not get involved in a cover-up.
Here Reagan strategists cite polls showing the high credibility rating of Reagan, running in the 70 percentiles and coming even from many Americans who may fault his handling of the economy and other problems. And they point out that although questions have been raised in the past about the conduct of CIA Director Casey, Secretary of Labor Donovan, and others in the administration, these charges have in no way scarred Reagan's image as a very honest, trustworthy President.
* But these strategists concede a gnawing worry: that this potential scandal poses a real threat, and perhaps the only threat, to Reagan's reelection; that the way the President deals with further briefing-papers developments, if and when they occur, may tarnish his image.
It is feared, in fact, that somehow the Democrats and the media will be able to portray Reagan as ''stonewalling,'' as not dealing forthrightly with the case. And that somewhere or other in the 1980 campaign an active effort may have been made by one or more in the Reagan camp to obtain this Carter information - under the guidance or sanction of a high Reagan aide.
Reagan strategists underscore the President's widely perceived integrity. But they acknowledge that, should the public begin to doubt that Reagan does not deal in an honest, open, and fair way, his occupancy in the White House for another four years could be threatened.