Moscow — Kremlin leaders seem to accept that martial law won't solve Poland's problems quickly or cheaply. They also have apparently given up hope of a serious split in the Western alliance - despite current transatlantic differences.
The Soviet Union is assuming that its ''Polish problem,'' economic and political, is not about to evaporate under Polish martial law.
On the economic front, the Soviets expect Poland to continue to run a large trade deficit with Moscow. The Soviet Union announced late Jan. 6 that it was extending ''easy-term'' credits to Poland to cover the imbalance and to facilitate further needed deliveries of Soviet oil, gasoline, and other resources.
On the political front, the official Soviet news media have pictured a Polish Communist Party undertaking a serious, and necessarily gradual, campaign to shore up its ranks. A recent Pravda dispatch from Warsaw spoke of ''the effects . . . of extremists'' in Poland as an ongoing problem.
''People's Poland is living through difficult days,'' said Pravda. ''Lying ahead is not an easy road: the road of stabilization, the restoration of economic balance, the strengthening of socialist foundations.''
Moscow also seems to have abandoned hope, at least for now, of a serious rift within the Western Alliance over how to respond to Poland's military crackdown. It is true that the West Europeans have balked at imposing economic sanctions on the Soviets. But the European Community has resolved not to undermine unilateral US sanctions.
And the Reagan administration, partly by reaffirming its commitment to arms talks, has won increasing European support for the contention that the Soviets must share at least indirect responsibility for the crackdown in Poland.
The Soviet news media strategy seems to have changed accordingly. At first, Moscow went soft on the Europeans and sharply attacked the US response to the Polish crisis. More recently, Soviet criticism of Western policy has embraced the Europeans as well.
But if the Soviets expect long-term difficulties in Poland, they also seem keenly aware of the importance of immediate developments in determining just how long that term will be. And how difficult.
Official media reports, however imperfect a mirror of Soviet policy they may be, suggest the Kremlin still entertains the following hopes:
* That international attention on the Polish crisis will ease with time (no news, as it were, would be good news) and that the Polish leadership will therefore get breathing space to implement its political and economic policy.
(Poland's foreign minister, expected here around Jan. 11, will be the first senior Warsaw envoy known to have visited Moscow since imposition of martial law. This is seen as part of an ongoing Soviet effort to portray the Polish crackdown as an internal matter undertaken by an independent and sovereign state.)
* That the battered Polish Communist Party will, under the umbrella of martial law, start healing its wounds and repairing its weaknesses.
* That some credible force from within Poland's (officially) inoperative opposition will help the authorities put Poland back together again. (It is noteworthy that although the Soviet media have carried attacks on a number of ''antisocialist'' and ''counterrevolutionary'' Poles since the imposition of martial law, Solidarity union leader Lech Walesa has not been among them.)
* That any toughened American response to the situation in Poland will produce the rift within the Western alliance that, so far, has not visibly materialized.
On the economic front, meanwhile, the Soviets hope, simply, that the Polish economy will get back on its feet.
Ideally, Moscow suggests, the West should extend further credits to the Poles rather than using this and other levers to ''interfere'' in Poland's ''constitutional'' imposition of martial law.
The fewer Western credits offered, diplomats here point out, the greater the pressure on Moscow to dip into its prized hard-currency coffers on Poland's behalf. There are rumors here -- at this writing, merely rumors -- that the Soviets have already done so to help Warsaw meet early interest commitments on its enormous foreign debt.
Polish sources here would not immediately confirm this, and said the soft credit for Poland announced Jan. 6 was a ruble grant to cover the two countries' trade imbalance.