The Carter administration has grasped the essential fact about the Soviet Union. It is that - 60 years after setting up shop with what was then the most exciting idea in the world, communism - the country is a bore.

It's got great military power and can make life difficult for us and our friends. This compels our prudent attention and underlies our efforts to tame the competitive aspect of Soviet-American relations and enlarge the cooperative aspect.

But the country is a bore all the same. When Khrushchev was booted out in 1964, with him went Russia's best chance of modernizing Soviet power, of adjusting political controls to better suit contemporary standards of economic performance and individual self-respect. For old Nikita, after serving Stalin well, had ended the terror and moved far, if erratically, to stop ruling by the knout. The Brezhnev crowd opted for stability and bureaucracy. That's where they still are. Expect for the people harassed by the state, nobody in Russia has done anything interesting - in literature, agriculture, statecraft, you name it - for years. The sum of their foreign policy is that, sometimes lightly, sometimes heavily, they throw their weight around.

Granted, some Westerners who bemoan this state of affairs do so disingenuously. The Soviet Union's loss, they imagine, has been the United States' gain: How much more formidable a challenger the Soviet Union might be today if its leadership had not been guided by its own myopia.

But I find this argument unpersuasive. A "modernized" Soviet state, one more open to reform within and to the multiplication of contacts without, would well be a more reliable partner world affairs, a country with less of a psychological need to flex its power.

This is, at any rate, the administration's premise. The Carter people seem to me to have few illusions about the nominence of a Soviet conversion.

They're not making American security hostage to Kremlin changes that haven't yet come about and may never. But they have an open-minded view of the Soviet potential for change.

Marshall Shulman, ranking State Department Soviet expert, sums it up neatly enough: "To the extent [the post-Brezhnev leaders] see their interest in a responsible involvement of their country in the world economy and the world community, they should not feel from what we do or say that this option is closed to them."

There is a paradox at work here. If the Soviet Union were in fact a live and interesting country, it would likely be involving itself more creatively in the settlement of political disputes elsewhere in the world and in the efforts of industrialized and developing countries alike to cope with their various economic and social concerns.

In isn't. Neither its example nor its advice is valued beyond the reach of the Red Army. It skimps on offering its civilian technology and aid. And this poses a problem to Washington.

Quite rightly, I think, this administration, building on work of its predecessor, is trying to take foreign policy beyond a single-minded concern with Russia, into a multi-minded concern with what Zbigniew Brzezinski calls "a world that has suddenly become politically awakened and socially restless."

But there are limits on how effectively the United States can move in this direction so long as the Soviet Union lags behind.

Thus one sees the spectacle of the United States going beyond the traditional containment of Soviet influence and power and trying to turn the existing largely neutral or negative internationalism of its chief adversary into a more responsible internationalism - in respect to both "hard" issues like the Mideast and "soft" issues like food, population and resources.

Thus an official like Shulman worries - he doesn't gloat - that "the Soviet Union seems not to have fully perceived how much the revolutionary transformations of this age have moved from the patterns of traditional Marxist-Leninist thought."

Some would say, of course, that the administration overvalues these "revolutionary transformations" and that it should stick to containment. Almost all Americans, I think, of whatever political persuasion, feel such jitters more or less from time to time.

In fact, as on most public questions, we straddle. To ovesimplify, the principal job of the Defense Department, which assigns most of its $110 billion budget to the task, is to practice containment. Increasingly, the job of the State Department is to deal with "revolutionary transformations."

This is not a bad division of bureaucratic labor. Its results should become increasingly evident as the Carter administration goes along.