FOR SOME TIME now, Washington has been witness to the spectacle of the Republican far right playing cat and mouse with a conservative Republican administration's arms control policy. Recently, the director of the Arms Control and Disarmament Agency, Eugene Rostow, was forced to abandon two of his choices for top agency positions in circumstances leaving his own authority, and tenure, in doubt. A dark cloud hovers over President Reagan's nomination of Richard R. Burt as assistant secretary of state for European affairs. The courtesies and rules that determined senators can invoke to get their way, and the weight of conservative senators at the White House, have kept Mr. Burt from being confirmed since May.

It is hard to imagine Mr. Rostow's not being enough of a hard-liner for Ronald Reagan's Washington. His real "fault" seems to have been his old- fashioned confidence that career officers could be as loyal to the administration's purposes as certified Reaganites--and perhaps more effective. The White House doesn't do him, itself or its policies any good by leaving Mr. Rostow in this limbo. If it lacks the enthusiasm for him, or the political courage, to offer the support a director must have, it should admit it and replace him.

An astonishing letter from Sen. Orrin Hatch (R- Utah), laying out one principal objection to Richard Burt, was put into the Congressional Record on Dec. 8. "We have been repeatedly informed by your colleagues (our italics) in the Reagan administration that your policy positions and conduct run counter to the best interests of President Reagan . . . ," Sen. Hatch said, accusing the nominee of dovish sabotage in 13 particulars ("You opposed the zero option for the INF talks. . . ."). Meanwhile, Mr. Burt is accused of violating an espionage statute for publishing, as a journalist working for The New York Times in 1979, a story disclosing steps the Carter administration was taking to verify SALT II.

Whether the "colleagues," who provided the ammunition against Mr. Burt, are denounced as snitches or hailed as whistle-blowers hardly matters. For, even if all their stuff is true, it merely shows he was applying precisely the informed, incisive viewpoint for which he supposedly was appointed. The president has pointedly reaffirmed his confidence in Mr. Burt's "loyalty."

As for the espionage charge, Sen. Charles Mc.C. Mathias (R-Md.) has read the Senate Intelligence Committee's classified report on what damage was done by Mr. Burt's Times story of 1979. He noted on the floor that there is such a thing as "instant declassification by a competent authority." We call it a leak, and we note that the Burt story was consistent with the Carter intent to assure people that SALT II could be properly verified. Sen. Barry Goldwater (R-Ariz.) has expressed his own concern about what the episode tells of Mr. Burt's judgment. He should remember that in 1979 Mr. Burt was acting as a journalist.

It is the way of these affairs to change shape as time goes on. There are now suggestions that the administration may be trying to win Mr. Burt's confirmation by making certain personnel, procedural or policy concessions. It would be laughable--if it were not so ominous that Ronald Reagan is under pressure from his right. Why does he accept this trifling with the nominees--and the dignity--of his administration?