THE PRESIDENT WON quite a victory on Thursday when the House voted to support him in a defense budget cut. Mr. Carter wanted to eliminate funds for a fourth Nimitz-class nuclear-powered aircraft carrier for the Navy. The Ford administration had been all over the place on this question, finally ending up in opposition to the carrier in the aftermath of the presidential election. But the real drive to eliminate the funds and, via them, the carrier itself, came from the Carter administration. It is possible that the legislators will at some point reverse themselves, but the victory looks pretty solid at the moment.

Understandably attention has focused on a rather poignant and dramatic aspect of the conflict: it pitted Mr. Carter against Admiral Rickover, the man he claims was his model and inspiration as a young naval officer. But Admiral Rickover was scarcely alone in lobbying for the nuclear carrier. And the conflict involved far more than a test of wills between two Secretary of the Navy sided with the President. But the carrier was strongly supported in Congress by the Navy's senior officers who testified in its behalf; and their defeat - first by a single vote in the House Appropriations Committee and then by 101 votes on the House floor - may mark an important turning point in naval affairs.

The Nimitz-class nuclear-powered carrier is a big, fast, fuel-efficient, expensive ship that can carry a bigger payload of planes and bombs than the smaller kinds of ships the White House and the Defense Department have in mind to build instead. The carrier for which funds were just eliminated would have cost around $2.2 billion to build. But the craft's very advantages - its size and power - make it too expensive to build in any great numbers; so with the Nimitz-class carrier you would be foregoing the possibility of having more ships in more places, and you would also be putting an awful lot at risk in so costly a craft that would be vulnerable to Soviet surface ship-based cruise missiles.

If the House decision holds, then, it could well mark a critical moment in the history of the Navy, a moment when a new direction was taken. That direction implies a Navy with greater numbers of smaller ships, more flexible, more mobile, less vulnerable to sudden wipeout. The wisdom of this course, as distinct from the more traditional emphasis on big, powerful ships, has been the subject of much serious argument in recent years. Mr. Carter has taken a side (and the right one, in our view), and his first engagement in the contest has been impressive.