When Winston Churchill first called for an East-West "parley at the summit" in 1950, he had in mind a Cold War council that, as he put it, "should not be overhung by ponderous or rigid agenda, or led into mazes of technical details, zealously contested by hordes of experts and officials drawn up in a vast cumbrous array." Another British prime minister, Harold Macmillan, talked 10 years later about taking the spectacular out of summitry by programming a "chain of peaks" whose regularity and growing familiarity would be good therapy even if no big deals were struck and no fundamental differences resolved.

That this ideal has not materialized is no reason not to value it as a test of the current precarious state of relations between the two great power centers of the world.

In the abstract, the Reagan true believers would have us believe the Soviet economy is crumbling, the communist system a proven bust; that the Soviets' Eastern European satellites are sullen if not mutinous; that communist footholds worldwide are for the first time the targets of freedom-fighting insurgencies. Regularly, we are told that the president's Strategic Defense Initiative was the 10-strike that brought unstrung Soviet negotiators back to the arms control bargaining table.

And yet, if we are to believe the president's Sept. 17 news conference rundown on the summit, only the distant deployment of defensive nuclear weapons is negotiable. The rest, including testing as well as research, is off the table because the Soviets are making a much bigger effort on their own SDI. To prove our mettle, we must test anti-satellite weapons because, again, as the president put it, "we are playing catch-up."

We are playing catch-up as well, in the pre-summit propaganda game. The Soviets, the president says, are unfairly raising false expectations: Gorbachev is downright disingenuous with his seductive offer of deep cuts in offensive nuclear weapons as a trade-off for a hold on SDI development. Like a football team pinning clippings of their opponent's loose talk on locker-room walls, the Reagan crowd seems to be going out of its way to psyche itself up, with the big game more than six weeks away.

Why? I would list two reasons in ascending order of importance. One has to do with "regularity." Nobody in the Reagan entourage has experienced U.S.-Soviet summitry. The other has to do with a question of whether the Reagan people really have the courage of their ideological convictions. While they crow out loud about America's "standing tall," they keep on agonizing, deep down: How tall? Tall enough to take risks with arms control concessions or a genuine readiness to countenance competitive coexistence as a basic principle? The mind set does not bode well for the November meeting.

If the administration is not ready to engage in any effort to find common ground on Gorbachev's opening arms control gambit, that leaves either minor cultural and trade agreements or some constructive effort to sort out and defuse serious differences and conflicts.

The latter is what the president says he has in mind. The word is that he will lay out a laundry list of grievances -- Afghanistan, Central America, Soviet support of Libya's Qaddafi, the Soviet arms buildup and so on -- while presenting Gorbachev with "facts to try and show them by deed, not word, that we are not an aggressor." At his press conference, Reagan expressed the "hope" that the Geneva discussions "could lead to a change in the relationship between the two countries . . . in which we can remove this threat of possible war or nuclear attack."

That's a purpose worthy of Churchill's original concept. But it is not likely to be achieved on his first try in two days under Geneva's bright lights by a second-term president with a long track record of no confidence in the possibility of change in the U.S.-Soviet relationship.