Soviet Russia and China were nominally a democracies, but both were controlled by individuals without checks.
Do you have any proof of this? Historical evidence is much the opposite, as the sources I have linked show you.
Stallin and Mau respectively.
Stalin was not without checks, nor did he control the entire USSR, according to historical evidence including internal CIA memos. Mao was forced out of power due to his failures with the Cultural Revolution, directly proving that checks not only existed, but were used.
Again, what history books are you reading that is saying otherwise?