Why Jews Born in the Soviet Union after WW2 May Marry other Jews

Let us imagine a large Jewish community in which many women re-married without receiving a gett and were totally unconcerned about the problematics of mamzerim. Their children then married the offspring of other (unproblematic) marriages, and so on. After some time, it would be impossible to reconstruct exactly who was descended from those original re-married women. Consequentially, all community members would be under the cloud of possible mamzer status, and the possibility of a future rapprochement with other Jewish communities would be bleak.

Soon after the end of WW2, rabbi Nathan-Neta` Olevskii, a deeply learned halakhic scholar and a keen observer of Soviet life, came to the realization that if no action were taken, the fate of all future Soviet Jews would be exactly as described above: they would be considered mamzerim and effectively cut off from any future reconciliation with their brethren around the world. My lecture will be devoted to explicating the bold, heroic, secret halakhic action taken by rabbi Olevskii to lift the pall of mamzer status from future generations of Soviet Jewry.