A week after President Reagan's meeting with Andrei Gromyko, administration stalwarts are laboring to construe the Soviet diplomat's clipped public comments in a way that demonstrates the promise a second Reagan term supposedly holds for Soviet-American relations. Given the president's lead in the polls, who outside the Republican crazy right wants it to be any different?

All but lost in the shuffle is the unambiguous Soviet assurance that in a first Mondale term Soviet-American relations would likely improve.

Reagan got from Gromyko an expression of readiness to talk about talks -- "not that much more" than the American ambassador to Moscow had already received, according to Ambassador Arthur Hartman. After Gromyko received Mondale n New York last Thursday, however, the Soviet news agency announced approval for "some ideas" of the Democratic candidate, "should they materialize in Washington's policy."

Tass did not identify these Mondale ideas. Mondale adviser David Aaron, who sat in on the meeting with Gromyko, told me Mondale had not presented particu- lar proposals and did not know specifi- cally what Tass referred to. Presumably, however, Tass had in mind Mondale's familiar proposals for brief halts in selected American weapons in order to break the ice and test the Soviet response, for a mutual negotiated freeze, or for an early summit.

Let us leave aside for the moment the merits of these Mondale ideas. To me it is noteworthy that Gromyko made crystal clear the Soviet view that, while a large question mark still hangs over dealings with Reagan, things would go better with Mondale from the start. So much, by the way, for the notion that in dispatching Gromyko to Washington the Kremlin was climbing aboard the bandwagon that is evidently carrying Reagan toward reelection in November.

Reagan had invited Gromyko in the first place, for one reason, to provide insurance for his campaign, so he was hardly in a position to complain that the Russians had in effect given the nod to Mondale. Half the White House staff would have been out on the South Lawn doing cartwheels if Gromyko had said anything half as benign about their man.

Still, neither the Republicans nor the Democrats have been keen to make too much of the Gromyko benediction. The Republicans do not want to advertise that the other fellow is way ahead in the Soviet sweepstakes. The Democrats, edgy about being considered soft, want Mondale to be known not as the candidate who is closer to the Soviet position but as the one better able to establish "common ground."

From the Reagan administration one hears regularly that the Kremlin succession is still up in the air, the post-Brezhnev crowd has yet to produce the single strong leader it needs to get off the dime, and so on.

What truth there may be in this analysis seems to me secondary to its aspect as an excuse for the Reagan administration's lack of achievement so far. The Mondale camp scores with its countering contention that Moscow's proposal last summer for space talks and its dumping of the Soviet chief of staff indicate a capacity for political decision-making substantially greater than any that the Reagan administration showed in approaching the Gromyko meetings.

It is relevant here that the White House was briefed promptly on the Mondale- Gromyko exchange, but, according to "a senior American official," neither the president nor Secretary of State George Shultz asked Gromyko what "ideas" of Mondale's he had found promising.

Shultz was asked about the Mondale approach to arms control on television Sunday. He did not simply say the administration had another view. He formulated the Mondale approach tendentiously, declaring there to be "no reason why we should . . . give (the Soviets) what they want in order to start discussions."

"The worst thing in the world," Shultz went on, is to give Moscow the idea that we want "an agreement for the sake of an agreement" -- an interesting comment, by the way, when placed against the report by national security adviser Robert McFarlane that "The specific value of (the Reagan- Gromyko) exchange was that our willingness to accept virtually any format or combination or agenda that they might like to propose was clear."

Shultz added: "You have to be relaxed about the need for an agreement if you are going to get a good one." Very few people are going to accuse the Reagan administration of being insufficiently laid back in this regard. And to think that Shultz is widely seen, and in some Reaganite quarters deeply distrusted, as the team moderate.