With military maneuvers, stern warning letters, and a fusillade of press criticism, the Soviet leaders have been stepping up their pressure on the Poles in recent weeks.
Now Moscow has added an economic dimension. A Soviet planning mission has arrived here amid indications that the Kremlin is telling Polish leaders that the scale of future aid will depend on more resolute political action to overcome the crisis here.
The delegation is headed by Nikolai Baibakov, who is vice-premier of the Soviet Council of Ministers and chairman of its planning commission. The fact that the head of the commission himself has come, less than two weeks since a Polish planning team was in Moscow, underlines the serious purpose of the visit.
This latest move comes just as this country is bracing for the second stage of Solidarity's national congress, due to open this Saturday. And it follows publication here last weekend of a Kremlin letter sharply criticizing the Polish leaders' failure to curb the anti-sovietism on display during the first stage of Solidarity's congress Sept. 5-9.
In that letter Russians offered none of their previous assurances of confidence and continued economic support. Instead they demanded immediate government action and an end to the leniency allegedly being shown to the "enemies of socialism" aiming to take over power in Poland.
The Baibakov mission had come at Polish invitation, a communique said, for talks "on the main lines of economic cooperation between the two countries in 1982 and in the years to come."
That is a wide brief. It suggests that the Soviets -- made uneasy by the magnitude of Polish investment in the 1970s and the catastrophic Western debt burden it subsequently incurred -- will be exercising much greater caution in their long-term economic dealing with Poland.
It looks, too, as if the Poles are going to be placed on a sort of probation to see if they are capable -- quite apart from the political action demanded of them -- of doing something to remove the present disequilibrium in their trade with the Russians.