We all know them- the people out there that accuse Obama of being a "socialist" or a "communist". But is he? That's a big question full of mixed up ideas and assumptions. I am going to try to deal with this as simply and un-theoretically as possible.
First off, a real "communist state" has never existed. That is why it was called the USSR and not the "USCR". Communism in a pure form was theorized most famously by Marx and Engels. They were dreamers trying to find a way to a perfect world, and the emerging capitalism they saw sure wasn't it. A perfect world would be everybody working for the common good, and everybody getting an equal share of it, while capitalism was based on driven individuals amassing wealth through their efforts and using only a part of it to improve conditions, just enough that the benefit they created added to that wealth. Instead of seeing mankind as advancing because of people gifted with intelligence and driven by opportunity, they saw only the (all-too-prevalent) dark side of those who were being left behind because of their lack of either, opportunity, intelligence, or motivation. They conceived an ideal of human freedom, in which all would benefit from each one's labor.
Of course, to have this kind of world, you'd have to have a population with an ethic of work and one of morality, willing to set aside both selfishness and individuality (I'm being general here; take this as the good and bad sides of individual freedom) to work for the common good. But in the world they lived in, Marx and Engels knew that what was established would have to be torn down in order to create this. In other words, the have nots would have to overthrow the haves. Only then, with everyone having an equal chance at prosperity would class divisions such as finances, nationalities, and religions dissolve so that, as another Lennon would say, "the world would live as one."
So there is the three highlights of Marxist thought- human freedom, proletariat revolution, dissolution of class lines. To gain this, you would have to have a proletariat savage enough to overthrow their rulers and kind enough to share; ambitious enough to build a new world and selfless enough to divide up the fruits thereof; intelligent enough to see themselves as better than their masters but equal to the masses that might be dumber than they.
Not much wonder that M & E never worked much on the practical applications.
Which is where Lenin comes in. Lenin is Russian, and he knows a few practical things. For one, the average member of the proletariat isn't that smart, isn't that ethical, and isn't that selfless. They will have to be trained. For another, people who have been trained over centuries aren't likely to give up "God and Russia" to make a better place out of a world they've never (and likely will never) seen. To accomplish this, he devises the concept of a "vanguard party"- a Deux ex Machina that will teach the masses, lead the masses, and when necessary, force the masses forward. Eventually, through a rule that brooks no opposing views, the proletariat will be brought to a point where they see the hows and whys of communist life, and then the party will wither away because everyone will do what is needful on their own. This was what socialism was, originally- a waystation between revolution and utopia.
But for this kind of communism, you needed a different kind of people: taught by centuries of being serfs to go along with everything they were told, uncomfortable enough with the old regime to try something new- and you would need a charismatic, stand out leader to get them to do it. Russia (and later China) had more than enough of #1. Number two could be created by stripping them of their religion- the one thing (outside of alcohol) that made the miserable life bearable; And the third, well, that's where "Grandfather Lenin," "Uncle Joe", and "the wise Chairman Mao" sprang from. So in leaping from theory to application, you had to change no state to one-party state, fairly intelligent masses to sheeple, and egalitarianism to cult of party and personality. Not surprising, then that Lenin's plan of government was based on "reaching a decision democratically, and once reached, everyone must support and promote it."
Lenin was like Marx, a bit of a dreamer. He saw the ugly reality of Stalin and tried on his deathbed to forestall the Stalinist future, without success. Stalin went further from Marxist ideals. Rather than try to eliminate nationalism to make a one world system, he used nationalism to promote the concept of "achieve socialism in one nation first; one established, then spread it." Rather than the party being a semi-democratic caretaker until true communism is achieved, Stalin made the state stronger, for several reasons (besides the main one of being a paranoid fruitcake). One, he saw the gradual path of Marxist-Leninism as too slow; they had to make strides NOW, before their enemies grew too strong and crushed them. Another, class warfare could not be complete until ALL advocates of a class society, real or imagined, were rooted out, because- of course- everyone was out to get them.
On the other side of Lenin's bedstead was Leon Trotsky. Trotsky was the ultimate Marxist dreamer. He rejected both the "socialism in one country" of Stalin and the "gradual, democratic path to communism" of Lenin. He saw a worldwide revolution as necessary, followed by an immediate move into pure communism, without either Lenin's "stages of capitalism" or Stalin's "copying of capitalism". Needless to say, he didn't remain popular too long; the flow of this kind of socialism was too rooted now in the "real world" to put up with utopian ideals.
Which is why Chia and the Soviets eventually fell out. Maoism was idealism in the extreme, a mad mixup of Confucian/Buddhist thought with Marxist economics. Unlike Lenin, who saw the worker as the powerhouse of change, Mao saw the farmer, armed and aimed, as the revolutionary dynamo. Where Lenin saw the party as the teacher, Mao saw the party and the people as learning from each other. He took on the Stalin concept of nationalism without necessarily adding the caveat of "this nation first, then the rest". And where Lenin's cult was based on his intellect and Stalin's on fear, Mao became an expert PR man, building himself into something like a modern day Confucius, a fountain of wisdom who was able to deflect hard problems with a philosophic shrug.
So the concept of noble communism, with human freedom as its goal, an intelligent, ethical workforce as its engine, and a classless society as its mantra, had become something else in application. Classless had become two-class (us and them); the Party had become both engine and mantra, means and goal; and freedom replaced by the "hive-mind" that did only what the party told them. Next time, how this worked out for them.