Grumbles are heard that the Russians have once again herded an American president into an "arms control summit," one in which they dominate the agenda and keep it trained on an issue that lets them wield world opinion against the United States. Somewhat in response, Ronald Reagan moved yesterday to broaden the agenda to include Soviet global conduct, one item -- human rights is another -- where he thinks the United States has the high ground.

But why is anyone grumbling? President Reagan is getting a bum rap. He is the last person to be suspected of panting for arms control and being prepared to downgrade the freedom cause. Why can't people just let him go ahead and use the summit to negotiate the negotiable -- arms control? The regional issues are at this point unnegotiable, or so it seems to me.

It's not easy for one great power to make the other account for its foreign policy at a summit. The challenged power can sit tight or, as Mikhail Gorbachev has indicated he may do, fire back. By going on the attack, Reagan may cheer conservatives. But Gorbachev can play to the many who feel it is "unrealistic" or provocative to raise divisive political questions, lest they get in the way of arms control.

In earlier summits, the possibilities of "linking" our cooperation on arms control to theirs on regional issues were sorted through, but this time there's been little talk of it. Ronald Reagan never got into the idea of explicit negotiated linkage. The idea of broad implicit linkage is now so widely accepted that nobody bothers anymore to assert it: naturally their conduct affects our president's inclination and freedom to deal with them. In any event, the Russians have met the relevant test: they haven't done anything especially outrageous lately.

In another day, the two leaders might meet and negotiate on specific political issues. But there is no hint that this will happen at Geneva. Regarding Afghanistan, which is the one dispute actually under negotiation (by the United Nations), the administration sees no break coming; most observers agree. Perhaps this helps explain why President Reagan stuck to a general approach to political questions at the United Nations.

But there's more. In preparations for the summit, the administration is advertising itself as above all realistic, not confrontation-minded, not naive: it doesn't expect Moscow to alter its fundamental goals, but it is going to try, in the nuclear age, to keep the inevitable political competition within prudent limits -- as it has for five years. Some of its briefings recall the traditional d,etente-era emphasis on "managing" the Soviet-American relationship, adding some touches of cooperation, wringing out some of the tension.

This current, which can fairly be called realistic, does run in Reagan's policy. But there's a competing one. Reagan promised a new assertiveness, and he has delivered. There is no secret about his belief that events were running the Russian way in the 1970s and are running the American way now. The strategic balance is deemed to have received the urgent repair it needed -- this in an administration that believes that from the strategic balance all else flows, not least the Kremlin's appetite and risk- taking proclivity.

This is, after all, an administration that angrily repudiates the Brezhnev Doctrine, by which Moscow assumed a right to police national deviations inside the Soviet bloc and to intervene for "progressive" forces outside the bloc. It is applying a "Reagan Doctrine" of promoting freedom: by political means in societies open to evolutionary change and by support for military means in societies closed to it.

Here is a characteristic Reaganite measure: In the late 1970s Soviet arms, troops or surrogates were involved every year in a new assault on an independent state: 1975 South Vietnam, 1976 Angola, 1977 Somalia, 1978 Cambodia, 1979 Afghanistan, 1980 Chad. In the 1980s the main resistance movements are those -- some with American help -- combatting communist governments in Afghanistan, Cambodia, Laos, Nicaragua, Angola, Mozambique and Ethiopia.

With all of this, it is odd to find Reagan criticized -- even more oddly, by some of his friends -- for somehow stinting on regional competition. What do they think he has been doing out there in the world? Are they thinking of anything more than lambasting the Russians on Afghanistan and Poland, for which a summit is scarcely needed?

Reagan, taking the high road, intends to open a discussion with Gorbachev on what troubles the United States about Soviet global policy. Well, sure, it's a good idea, as long as he is ready to hear what troubles the Kremlin about American global policy. It could make for an important discussion -- an extended one. Meanwhile, there is arms control work to be done.