When did Democrats get overtaken by the Communist Party?

Back in the 1930's FDR sent a fact finding comission to Soviet Russia to checkon how the new style socialist/communist goverment was faring there, Stalin had an entire village and town built just for the occasion. Of course it was full of happy smiling productive people with loads and loads of new cars on the roads and items on the grocery shelf. The comission reported back to FDR just how swell and dandy this new stle communism was. A LIE that FDR bought into hook line and sinker and a BIG LIE that persists today.