The biggest obstacle to the plan's implementation soon proved to be the Berlin Blockade by the USSR, which was followed by a western counter-blockade of the Soviet occupation zone. As there were long-established economic ties between the western zone and the eastern, which was highly dependent on supplies from the West, the blockade was more damaging to the East. The West Berlin SPD newspaper "Sozialdemokrat" reported in April 1949, how Rau clearly criticized the blockade in a meeting of SED apparatchiks and there is reason to believe that he did the same in the meetings with the SMAD. According to the paper, Rau spoke of a "bad speculation" regarding the undervaluation of the dependence on western supplies, stating that the "broadminded Soviet help" turned out as insufficient and hinting that the blockade would soon be lifted. Finally the Berlin Blockade was lifted on 12 May 1949.