THERE IS PLENTY of mystery all right about the president's Camp David sojourn, especially if you concede that all mystery lies at least in part in the eye of the beholder - so that whoever proclaims himself to be mystified, is. But more than subjectivity is at play. There are real mysteries too. The circumstances and considerations that led the president to cancel his energy speech so summarily and to emit only Delphic signals for a couple of days and to engage in this unexpected summer retreat with its unknown agenda and elusive timetable and now its stream of visitors - none of these things has been sufficiently explained, either by those who are in a position to explain them or by those who aren't but usually don't let that get in the way.

So, first off, let us stipulate mystery. Having done so, it is possible to move smartly along to reckless speculation. You don't have to be some kind of reader of entrails, after all, to know - it is no mystery - the following things: that Jimmy Carter's presidency had reached some sort of political nadir by early July, that the politcs were terrible and the economic prognoses worse, that the energy disaster represented the heart but not the whole of it, and that the people and institutions (public and private) that make up the society seemed to be coming apart in a mean, scared, explosive way. It was in this context that the president first undertook to deliver an energy message on television last Thursday night - and then without a word of explanation canceled it. If, as both inference and some information strongly suggest, he did so because he believed a business-as-usual energy pronouncement (it would have been his third) was utterly inadequate to the situation and only marginally related to the larger problems facing him and the government, then he did something exceedingly wise.

People like to talk about the politics concerning a president as if this wer something separate from his governmental life, a kind of dread deadline by which he must make things A-ok or go down to ignominious defeat with all the rest of us watching. That's not it. A president's political strength is inseparable from his ability to govern, each feeds directly into the other and depends on it. For this reason political considerations, so often dismessed as self-seeking or cras in the context of national turmoil, deserve to the prime in the president's thinking just now, as they reportedly are. The 1980 election is not the question - in fact it will be moot if another prior question is not addressed first. How does Mr. Carter reestablish his all-but-disintegrated political authority? How does he recreate that peculiar combination of personal, political and institutional strengths that is the force of the office?

Not by formulating another one of those partial, accident-prone energy responses; not by coming on the air and telling the nation "I told you so;" not by putting forward a check list of accomplishments that people are meant to view as an alternative to the reality they live in and perceive. Mr. Carter presumably saw the inadequacy of these responses. And he also saw the dimension of the trouble: huge. He evidently recognized one of those moments when you take the lesser, pinprick risks and sustain the lesser, pinprick complaints in order to call a halt, reexamine everything - radically - and not be hurried or deflected.

The result is that they are apparently reinventing the Carter administration at Camp David, or trying to. The thought seems to be that, unless there can be a restoration of political authority and confidence and generosity and willingness to do tough things - with or without more gas. The president is also said to be determined to try to find the way to use his office to bring the warring elements of the political/social/economic scene into at least some common appreciation of national danger and national needs.

That, not merely working out yet another list energy priorities to try (unsuccessfully) to impose from on high, is what he should be doing. No one can look at this indisputably odd event and be wholly reassured. And no one can look at the disarray that drove Mr. Carter and his small company to the Catoctins this weekend and feel only sympathy. It's not as if the administration's own mistakes and follies had not had plenty to do with the way things now are for them and everyone else. But the president seems willing to acknowledge and deal with this, and to try to do so in a way that will get the country's half-dry, rasping social engine going again.

If that is in fact what the mystery portends, Mr. Carter will have been undertaking an act of political courage as admirable asit is rare.