Like weather in March, the new superpower relationship runs both hot and cold

As was expectable, and expected, the second week of the new Soviet-American experiment in easier relations has been marked by rhetorical backtracking. Each side brushed up old cold war slogans to pacify their respective hard-line critics who fear that all this new hands-across-the-iron-curtain business may go too fast and too far.

The Soviets pointedly ignored President Reagan's invitation to a ``summit'' and their point man in Geneva, Viktor Karpov, accused the United States of already trying to back out of its pre-Geneva promise to negotiate all aspects of arms control without preconditions.

President Reagan did his bit for his own anxious hard-liners by reaffirming his conviction that the Soviets violate treaties and run an empire marked by ``human beings persecuted, religions banned, and entire democracies crushed.''

The first week of the experiment had been marked by euphoria. The opening of the new round of arms talks in Geneva was topped by the emergence of a new Soviet leader, Mikhail Gorbachev, and Mr. Reagan's invitation to him to visit the US. The Western press speculated about a new era of d'etente opening up between the superpowers.

This was enough to strike terror in the hearts of hard-liners on both sides of the great-power divide. The d'etente of the Nixon-Kissinger era is a bitter memory to the American right. It meant a run-down in military procurement. It also meant accepting the existing Soviet empire rather than practicing a ``roll back'' of it.

Without an officially proclaimed ``Soviet menace'' the weapons budget languishes in Washington. Does the same thing happen in Moscow? That it does is intimated by the surprising disclosure this past week of a partial text of a speech Soviet Foreign Minister Andrei Gromyko made at the secret session of the Kremlin at which Mr. Gorbachev was confirmed as successor to Konstantin Chernenko.

In that speech Mr. Gromyko, a leading Kremlin hard-liner, seemed to go out of his way to assure his friends, including the military leaders, that Mr. Gorbachev was no appeaser of the US.

Among Kremlin-watchers the theory is regarded as plausible that Mr. Gorbachev won acceptance in return for assurances that he would not abandon their interests for the sake of a deal with Washington.

American hard-liners and self-styled ``neo-conservatives'' have pre-positioned themselves for the present experiment by getting on the record as saying that Mr. Reagan has already abandoned the true conservative faith in foreign policy. They want ``roll back,'' not accommodation.

Norman Podhoretz, editor of Commentary magazine and chief philosopher of the ``neo-conservative'' movement, put his disappointments and fears into an article just printed in a special issue of Foreign Affairs magazine (Volume 63, No. 3). In it he says that during Mr. Reagan's first term he ``proved unwilling to take the political risks and expend the political energy that a real break with the underlying assumptions of d'etente would have entailed.''

Hence Mr. Podhoretz foresees ``negotiations with the Soviet Union not merely on arms control but towards an agreement along the lines of the Basic Principles of D'etente of 1972.''

To Mr. Podhoretz this means Reagan ``will cruelly disappoint those of us who once hoped that he might lead the Republican Party into assuming the responsibility for resisting Soviet imperialism. . . .''

In other words this second week of the new Soviet-American experiment in moving was noticeable for the efforts of hard-liners in both countries to contain and restrain the movement toward easier relations.

Bad relations between Moscow and Washington are preferred by important group interests in both countries. True ideologists exist in both and both shun trafficking with the enemy. The military-industrial complex in both thrives in bad relations, is endangered by any easing. Part, not all, of the politically influential American Jewish community favors the hard line toward Moscow and was prominent in the original campaign against d'etente.

President Reagan is therefore embarked on an experiment which is by no means popular throughout the American political community. It is least popular off on the right of his own constituency, which was shocked when he embraced mainland China, deeply disappointed by his failure to practice active ``roll back'' in Eastern Europe and his failure to overthrow Fidel Castro in Cuba, and is deeply distressed now at the opening to Moscow.

The only things he has done in foreign policy since taking office that genuinely pleased his own right wing were the invasion of Grenada, the backing of the regime in El Salvador with guns, the mobilization of the contra rebels against the ruling Sandinistas in Nicaragua, and the big arms program.

Otherwise his rhetoric has been on their side, but his actions have left them disappointed.

The remaining question is how far Mr. Reagan dare go down the road toward another experiment in easing relations with Moscow. Can he appease his hard-liners with rhetoric? He was doing his best this week, but also hewing staunchly to his military budget. So long as he stays with that, his right will complain and express ``dismay,'' but probably will not break.

We can only speculate about how much leeway Mr. Gorbachev will have in Moscow. Obviously, he does not yet have permission from the majority in the Politburo to seize the invitation to a summit with Reagan. Perhaps the suggestion was rushing the game.

All of this means that for both Reagan and Gorbachev the road toward easier relations will be narrow and stony and beset by many a formidable obstacle. Peace is not going to break out tomorrow.