Will Baker or Casey have to go?

Some columnists now write that those key administration Reaganites, Jim Baker and Bill Casey, are involved in a shootout in which only one will survive. Soon the President will have to choose between his chief of staff or his CIA chief. One will have to go.

Maybe.

No doubt that there is friction between the two men, compounded by a difference of opinion over how the Carter debating papers were accepted into the 1980 campaign. Baker's recollection is that they came from Casey. Casey says that he has no recollection of having seen the document and that it was a mistake for such papers to have been used by the Reagan people - thus pointing the finger at Baker's judgment.

Those who like to deal in high drama in this city see the Baker-Casey confrontation as the climax of a struggle between the GOP right wing and GOP moderates which has been going on since Reagan moved into the White House.

These sometimes rather imaginative writers have worked out this lineup: Leaders of administration conservative team - William Clark, Edwin Meese, and Casey. Leaders of administration moderate team - Vice-President Bush, Jim Baker, and Mike Deaver. These antagonists are supposed to be continually vying for presidential favor, each side hoping somehow to oust the other.

But the main force behind this struggle is supposed to be the party's far right, which is said to see in Baker's acceptance of the Carter documents the very blunder it needed to persuade the President to drop him from his administration.

Who are these right-wingers? And are they indeed trying to prevail on the President to get rid of Baker? If so, will they be successful?

Frank Fahrenkopf, Republican national chairman, said at a breakfast meeting with reporters that he was in constant touch with GOP state chairpersons, many of them con-servatives, and that he had not heard ''a single word'' about anyone wanting to get rid of Baker. He said that he knew of no effort from the conservative wing to ''get Baker.'' And that he doubted the President could be persuaded to drop Baker even if anyone was trying to get him ousted.

Fahrenkopf is not exactly an objective observer, of course. He would be expected to convey that harmony still prevailed inside the administration. But soundings among GOP leaders evoke a similar response. No one I have conversed with mentions any concerted effort to reshape the administration staff - and particularly those who deal with Reagan on a day-to-day basis - along more conservative lines.

One influential White House aide was asked the other day: ''How much of a struggle is going on?'' His answer: ''About 50 percent less than these writers are saying there is.''

Bryce Harlow, who has been a close-in observer of presidential administrations since Eisenhower, says there are always ''troublemakers'' who foment strife ''within all White Houses.'' ''They usually are second-level people,'' says Harlow, ''who stand to gain by changes or who simply like to gossip and cause friction.''

Harlow thinks that it is such lower-level aides who are causing most of the trouble and ''sourcing'' most of the stories depicting a massive power struggle in the Reagan camp.

This is not to deny clear differences among the President's top men. At first Deaver, Baker, and Meese seemed to be meeting in near-perfect harmony. Now they admit they often don't see eye to eye. Deaver concedes that he and Baker tend to approach problems in a similar way and that they sometimes arrive at solutions that differ with Meese's and, on occasion, with Clark's. But he insists these differences are more a matter of ''style'' than anything else.

This reporter's judgment is that there still is a considerable amount of unity among the top hands in this administration and that the differences of opinion voiced still fall within the context of ''relative harmony.'' Moreover, So does Baker or Casey go? Possibly. But my guess is that the President values both men and will not be quick to let either go.