HAS the Reagan administration backed away from the merit plan for the selection of judges that the Carter administration tried so hard to install? The answers are pretty murky. Evidently, the administration has in mind nothing so sharp as was suggested in this newspaper the other day. Nevertheless, the battle to divorce the selection of judges from purely partisan politics has been fought for so long by so many administrations that any step back toward senatorial control, even a tiny one, has its large implications.

This is why the administration's insistence that it is "firmly committed" to the principle of merit selection was received somewhat skeptically on Capitol Hill. By eliminating the judicial selection panels former attorney general Griffin Bell struggled to create, the administration made itself vulnerable to suspicions that senators, once again, are going to control the appointment of federal judges in their home states. This is underlined by the peculiar language in a memorandum by Attorney General Smith that says that he, the attorney general, "may, when appropriate, make recommendations" to the senators about specific judicial candidates.

Perhaps Mr. Smith doesn't intend to let the senators take over as much of his job and the president's as the memorandum suggests. But if he doesn't, he may soon learn that the process by which judges are selected is a treacherous one even for those with the best of intentions. There are always senators around who will use every power they possess to turn their right to "advise" the president into a right to make appointments. Only time, and a series of judicial nominations, will reveal whether Mr. Smith has yielded too much to the senators of his party.

The Republican senators from Maryland and Virginia (Charles Mathias and John Warner) are far from inclined to use whatever voice the Reagan administration has given them to try to pack the federal judiciary with political cronies. Sen. Warner has inherited the unhappy situation in which a confrontation between President Carter and Harry Byrd has left two Virginia judgeships vacant far too long. He has promised to seek out female and black candidates -- the issues over which Mr. Carter and Sen. Byrd collided -- and that is what he is doing. The point needs to be acknowledged.