WHAT WE ARE beginning to resent more than anything else about the case of the captured Carter document is the amount of time and the exertion of thought necessary to sort out its various moral and political implications. An overwrought press and an underwrought political establishment have not made the job any easier. How distinctive was the acquisition of the Carter debate-briefing book by the Reagan campaigners? What should the act of acquisition itself be called? A leak? A theft? A commonplace campaign-intelligence maneuver? And what should happen to those responsible for appropriating this document? Anything?

The answers to some of these questions depend on information not available to us yet. Certainly prying loose the other side's campaign secrets concerning tactics, strategy, skeletons in the closet and anything else of consequence has long been a staple of election activity among candidates of both parties. Our society seems to make some kind of distinction between how you get that material and how you use it. We are much more tolerant of sleazy uses, it seems: campaign literature and lore abound with stories of ghastly extortion-type trade-offs in campaigns--arrangements whereby each side undertakes not to reveal some disgusting or inflammatory thing it has unearthed about the other in return for silence on its own weaknesses.

Some readers and onlookers appear to be amused, entertained or titillated by all this, others merely indifferent to it. But the means by which the parties may have acquired their damaging information in the first place are something else again. Here there is an infomal, publicly understood code of behavior. Watergate confirmed some of the limits: no breaking and entering, no abuse of official powers--i.e., police or prosecutorial or intelligence-agency resources--to get the goods on a political opponent or to intimidate him. And, although the planted agent in the other side's campaign is a fairly familiar feature of campaign life, there is still a feeling among laymen that this is a damned dirty and underhanded trick.

So which was it with the Carter document? The answer awaits the inquiries going on. We think it will make a real difference if someone was sent in to swipe it, for example, as distinct from someone's merely receiving the briefing book as leaked goods. In this connection, we don't mind cautioning some of our fellow journalists that a profession which has insisted as firmly as ours has--and with good reason --that leaked presidential (and other governmental) material is not stolen goods might be just a tad more careful about maintaining the distinction.

President Reagan says he didn't know the people coaching him for the debate had this briefing material from the Carter campaign. He would be mad to make such a statement if it were not true, given the number of sleuths on the case, and we presume it is true. That does substantially improve his position: better he didn't know than that he did. And we are also a little leery of the argument that the acquisition of this document, even if only by his coaches, made the crucial difference for him in preparing for the head-to-head contest with President Carter. Ronald Reagan, as was seen in the preconvention period of the 1980 campaign, has a certain talent for prevailing in public debate with opponents said to be better informed than he.

What it comes down to then for us is this: something not quite cricket happened. That this may be unexceptional in political campaigns or that it may not have had a crucial effect on the outcome of a crucial debate does not much mitigate that fact. The Reagan people had something analogous to the questions for the test in advance, and this, even in so artifically constructed and prodigiously scripted an event as the presidential debate, offends the sense of fairness. Whether something more serious and far worse occurred awaits the information as to how that document was acquired in the first