Here is an effort to rescue one of the Reagan administration's most intriguing foreign policy statements -- a speech in California on Aug. 19 by Robert C. McFarlane -- from the negative and (worse) dismissive comment in which it was quickly wreathed.

The effort seems worthwhile not simply to be fair to the president's national security adviser but also to perceive more clearly the Reagan approach to the scheduled November summit with Mikhail Gorbachev -- as presented, anyway, by the man currently riding a wave of celebrity as an ever more influential presidential aide.

Reading of the speech on vacation, I was prepared to believe it was, as described out of town, either the usual hard line of a hard-line administration or an extra thumb in the eye designed to be packaged, for devious pre-summit purposes, with similarly designed decisions 1) to go ahead with a test of an anti-satellite weapon and 2) to go public with complaints about "spy dust" in Moscow.

Reading the speech on return from vacation, I found it an unusually reflective and fresh invitation -- although one not entirely free of disfiguring cant -- to the Kremlin for a serious dialogue. If the speech is not the tip of an iceberg whose bulk includes some heavy presidential correspondence with Gorbachev, then the administration is falling down on the job.

"Soviet Must Shift on Major Issues, M'Farlane Insists," said a typical headline on one news story. But what McFarlane actually said was that the Kremlin leadership -- which the administration has depicted in the past as ice-bound by age and ideology -- is now in a posture of "considerable flux and introspection," and that if a proc review is in fact beginning, it may help Moscow to hear "what we're after." Hardly a peremptory demand.

By way of explaining what in Soviet policy troubles us, McFarlane emptied out a mixed bag: pushing on with chemical weapons after the United States stopped making them, upsetting the European balance with new SS20s, going beyond the "understandable" desire for a friendly Afghanistan by putting in 120,000 troops, providing submarines to Libya's Qaddafi and giving him missiles that end up being fired by Iran into downtown Baghdad, making Cuba in the 1970s a major Soviet-American irritant after a 10- year lapse, and accusing us of pursuing a first-strike capability with the Strategic Defense Initiative even while themselves conducting "the largest research program on earth."

Has the Soviet Union benefitted from these initiatives?, McFarlane asked. "We hope this question is being asked in Moscow."

No doubt Moscow has questions for Washington, but surely this one is fair. Is there any reason for holding a summit in which matters such as those McFarlane cited are not treated?

The United States has a way to go -- notably on the SDI -- to make good on McFarlane's assurance that President Reagan is ready to meet the Soviet Union halfway on the issues. But is there not self-evident truth in his companion assertion that "without some change in the Soviet approach to security issues, in fact in the thinking that underlies it, I fear that even incremental improvements will be extremely hard to reach"?

"Far-reaching" improvements in Soviet-American relations, McFarlane observed, are bound to await internal Soviet change. He was referring to progress in human rights and to a need for government to afford individuals space for economic and cultural play. Soviet officials and some Americans were bound to find this formulation preachy and intrusive.

Yet this has been the guiding principle of American policy at least since George Kennan recommended that the United States practice "containment" until the Soviet Union mellows. It makes a big difference how this principle is put into practice, but that it is a sound principle I do not in the slightest doubt.

A smart Soviet would be paying more attention to McFarlane's careful effort to show -- by reference to President Reagan's approval of changes now being made in China -- that the administration is open in its world view to a "recognizably socialist" country, if it starts lengthening the leash on its people.

Positions on issues are central to pre-summit strategy, and in terms of issues neither side is giving away early freebies. But the tone each uses has its own importance, not just in making propaganda but also in conveying hints of which direction a positive mutual flow could go. Some may find McFarlane's tone syrupy and disingenuous. I find it relatively earnest and helpful. The Soviets should pay attention.