Yeltsin made the job easy for him, banning the CPSU from the beginning. And even against its offspring, they both had to rig the elections for a whole decade. All this with the acquiescence of the west. By the time the US and its allies started wondering if they wanted Putin at the helm of Russia, there was no one left to oppose him. So yes, nowadays Russians can vote whatever they want, just as Americans can vote whatever they want, with a slight difference; the facade of democracy can be maintained on the US, because there are two "options", while in Russian you only have one. Now, if Medvedev had a fake kerfuffle with Putin, and founded "another" party promising completely different policies, but that would end doing the same... then the charade would be good.