IT IS AN overwhelming moment: on the events of the next few days in Poland may turn a very large part of the course of global politics in the 1980s. If the Poles continue the valiant, tormented effort they have made since August to resolve peacefully the tensions between the people and the government, then it is possible to look ahead with at least some cautious hope that the worst will not occur. But if either the Polish authorities or their Soviet overseers move to break off the dialogue and impose a one-sided solution by force, then things will be very dark -- and not only for the Poles.

Repeatedly in the last month it has seemed that there was no way to keep balance the workers' demands to speak for themselves and the party's and government's insistence on preserving a monopoly of power. Careful leadership, a measure of patriotism and a shared commitment to socialism and to alliance with the Soviet Union, on both sides, have prevented an irreparable break so far.

In the latest crisis the sense is heavy that matters cannot be allowed to lurch forward longer without prospect of reasonable and foreseeable resolution. The workers' courage is awesome -- witness their unprecedented giant "warning strike" yesterday. They can hardly be expected to maintain that pitch of risk and participation indefinitely. The authorities, or the more frightened elements among them, seem to be at the outermost limits of their tolerance for change. Presumably the Soviet Union has counted all along on the possibility that finally events would erode the morale and common purpose that have sustained honest Poles since August in their struggle to find a new Polish way.

The Reagan administration issued an extraordinary statement on Thursday. It warned not only the Soviet Union but also "Polish authorities" not to bring force to bear. In this first allusion to the prospect of official Polish violence, the statement represented a far-reaching attempt to influence the internal affairs of another sovereign state. It was, moreover, a statement with teeth: American readiness to deal with Poland's economic difficulties was specifically conditioned on official Polish as well as Soviet forbearance.

Still, no one can doubt that the principal decisions affecting Poland are being made in the Kremlin. No crackdown could come, such as the imposition of martial law, that did not flow from a Soviet order. Such an intervention, the White House underlined, "could have a grave effect on the whole course of East-West relations." That is the somber truth.