It was Polish leader Wojciech Jaruzelski's first known trip to Moscow since martial law. He is likely to get at least two things from the men of the Kremlin:
* Continued economic backing for Poland's shattered and debt-ridden economy.
* Support for cautious dialogue with some members of the suspended Solidarity trade union.
But the central questions about the Jaruzelski trip, diplomats here say, are:
Will any such dialogue with Solidarity members work? And can any formula be found for long-range political and economic stability in Poland in the wake of martial law?
''No,'' is the way many foreign diplomats are answering that question.
''Yes, but the process will necessarily be complex and difficult,'' is the consensus reply of various Soviet officials interviewed recently.
With the ultimate answer unknown, the Soviets mounted a welcome for General Jaruzelski that was much warmer than those put together for visits by his immediate predecessor, Stanislaw Kania.
Strikingly warmer, too, was a banquet address made by President Brezhnev after a first round of talks. According to the news agency Tass, Mr. Brezhnev said the talks had been marked by ''an identity of views'' and by ''an atmosphere of friendship, comradely solidarity, and cordiality.''
Mr. Brezhnev's speech included a nonspecific pledge of further Soviet aid: ''We shall continue helping'' Poland, he said. ''These are not just words. There is no doubt that both our countries will benefit from the plans we made for economic cooperation. . . .''
The Soviets' welcome began well before the Polish general's arrival. Moscow pointedly announced Jaruzelski's visit before last week's meeting of the Polish Communist Party's Central Committee. Diplomats here saw this as a concerted effort to demonstrate Kremlin support for him.
''It was a vote of confidence,'' remarked one Western ambassador, ''maybe in case anyone (in Poland) had other ideas.''
Soviet President Leonid Brezhnev greeted General Jaruzelski at the airport. A banner, in Polish, spanned the road into town, announcing: ''We welcome the party-state delegation from the Polish People's Republic.''
The official Soviet news media gave wide play to the visit. Immediately after imposition of Polish martial law, some diplomats here speculated that the Kremlin might be uneasy with the prospect that under General Jaruzelski the Polish military could usurp what Soviet ideologists term the ''leading role'' of the Communist Party.
Soviet officials at the time privately dismissed this idea, noting that General Jaruzelski was also head of the Polish party. They suggested that, in any case, the main immediate imperative was stability in Poland.
Initial Moscow media coverage of the Jaruzelski visit seemed to suggest much the same thing: The general was identified not as head of Poland's ruling military council but as the chief of the party and as prime minister.
Asked shortly after the Polish leader's arrival whether the welcome was meant generally to convey strong Soviet support for him, a ranking Soviet official replied: ''Of course.''
''Realistically,'' he added, ''there is no one besides Jaruzelski in any case. . . . We want the situation to become normal. We must start from the existing reality.''
The official, a member of the Soviet party Central Committee, spoke of a ''good impression'' in Moscow from General Jaruzelski's keynote address at the recent Polish Central Committee session.
''The (committee) plenum suggested the current Polish leadership feels, in a certain sense, in control. . . . This is something that could not be said about the preceding one.''
Conversations with this and other Soviet officials - and with foreign diplomats - suggest some likely features of Jaruzelski's talks with Kremlin leaders:
* A public Soviet bid to present the dialogue as a meeting between equals, to counter Western charges of Kremlin interference in Polish affairs.
* A pledge of continued Soviet aid to Poland's still stumbling economy. (The Soviet Central Committee member said such assistance would include ''help in filling gaps caused by the West's economic sanctions'' on Poland. He did not specify whether this would apply to coverage of Polish debt payments to the West.)
* Privately communicated support for cautious dialogue between General Jaruzelski and some elements of Solidarity.
''We hope for such dialogue,'' said one senior official, who stressed that the Soviets did not want to see a resurgence of what he termed ''destructive political'' action by the union movement.
Ideally, this and other officials suggested, Moscow is hoping for gradual political entente in Poland coupled with necessarily gradual economic recovery.
A prominent Kremlin spokesman, Leonid Zamyatin, said publicly Feb. 27 that ''counterrevolution'' in Poland had been checked, yet not totally defeated. But diplomats and other Soviet officials suggested this was less an indication the Kremlin wanted General Jaruzelski to get tougher, than an indication for domestic consumption that further Soviet economic aid to the Polish regime would be necessary.
Foreign diplomats here, initially skeptical of private remarks by Soviet officials indicating support for some kind of dialogue with Solidarity, are now taking such comments more seriously. One initially skeptical ambassador said privately: ''I believe . . . that there is talk (among officials) here about the need for some sort of reform'' as part of General Jaruzelski's bid for political and economic stability.
But the diplomat added that he saw no indication that the envisaged compromise would go far enough to work.