THE ORDINARY BUSINESS of American and Soviet foreign policy has halted. These days everything falls into a category called pre- summit maneuvering. Ronald Reagan and Mikhail Gorbachev surely know there is life after Geneva. But the two are in the grip of a summit dynamic, positioned to gain what is possible there and, otherwise, to escape the blame.

Doubters had feared that even so strong a conservative as Ronald Reagan would be swept up by a summit: a context in which he would be put under public pressures not falling equally upon his Soviet counterpart and forced into unwise concessions. This is the classic Reagan critique of 1970s-style d,etente. From what we see, however, it is foolish to be anxious about Ronald Reagan. He has not abandoned a hard line. And why at this point should he? He is dealing with a tough adversary. The political requirement to look reasonable arriving at Geneva cannot be permitted to undercut the national-interest requirement to leave room for give- and-take bargaining there.

Mr. Reagan is not everywhere regarded, of course, as ready for serious bargaining. But it's interesting that the Russians seem to be making their summit preparations on the premise that he is ready. Surely that is some part of the reason why they have decked out their positions for public viewing. On an issue of special sensitivity to both countries, they have moved toward acknowledging -- they have a good way to go -- that their Krasnoyarsk radar is indeed a treaty violation and requires correcting.

One day President Reagan says the first need is to raise regional, bilateral and human rights issues in order to eliminate "suspicion and paranoia" from the Soviet-American relationship. The next day he slides away. But it's hard to see how he could do it very differently. It is essential that he raise the troublesome issues that so deeply color Americans' perception of whether and how the United States can get along with the Soviet Union. It's also essential that he not put unreasonable obstacles in the way of what prospects there may be for arms control, which offers the set of Soviet-American issues most politically urgent and most open to negotiation now.

To Mr. Gorbachev's arms control plan of October, Mr. Reagan is now making the American response. Only the outlines of it are public but, as a realistic observer would expect, it appears to offer Moscow both some new openings and some new choices, none of them easy. It includes at least one initiative -- abandoning mobile land-based missiles -- which moved some of Mr. Reagan's domestic critics to instant objection. Our hope remains that the president and Mr. Gorbachev share a requirement not simply to look good but to put Geneva to constructive purpose.