The idea that human familial relationships are tied strongly to a dawinistic need to propagate a genetic line is false on its face. If this were the driving factor behind familial relationships, then we would have no adoption, we would provide no support for in-laws, we would in fact have no reason to provide support for parents or grandparents (since their genes have already been passed). The theory of genetic determinism is far too limited to explain the ways that humans form altruistic relationships (and is starting to be shown to be false in other animals, specifically vampire bats).
If we argue instead that altruism is based on enlightened self interest and that we are charitable to others in the hope that we may later be the recipients of such charity then we have a much more defensible argument, though I still don’t believe that it holds up. If it were so, then we would expect the most charity from the least secure, and we would expect charity to be doled out in ways that we would expect to need it. There is some weak evidence of this, but very weak in my opinion. The very wealthy under this argument would have ever decreasing altruism, but we tend to see just the opposite.
Instead I put forward the following theory of human nature. It seems deeply set in human nature to divide the world into “us” and “them.” Who is “us” and who is “them” is incredibly arbitrary. While there is a natural inclination towards genetic bonds, in various cultures we see “us” extended to unrelated companions (“friends”), nationals (even of varying races), legally adopted relatives, those of similar beliefs (particularly religious), those who have gone through similar ordeal such as war, those who have been initiated into the same organization (fraternities), etc.
“Each giving according to his gifts; each taking according to his needs” works as long as all the members share a bond and feel obligation towards each other (thus discouraging and dealing with free-loaders). When it falls apart is when the members do not feel these obligations, which most easily happens when the members do not know each other (which becomes harder as the society grows larger).
It is difficult to legislate this attitude, which is why national communist societies have generally failed. I would argue, however, that it is equally difficult to legislate the attitudes required for democracy, which is why so many of the democracies in Africa and South America fail. Since the Magna Carte, and definitely with the US Constitution, western culture has instilled in its people the idea that we are governed by law not individuals. At no point during the Bush/Gore struggle for the Presidency did anyone fear that one side or the other might turn to violence to install their chosen leader. To do so in our culture is unthinkable. Try to imagine Gore calling for armed revolt. But such a thing is common in other cultures; even expected.
For a communistic society to flourish on a national level, the people would need to consider all members of the nation to be part of their family. If that were a core ideal of the culture, then I think a democratic communist system could work well and likely better than the current democratic capitalist model (which has inefficiencies that are not often seen in families). This idea is no more alien to human nature than the idea that the “unwashed masses” can govern themselves through elected leaders without creating a tyranny of the majority or the people “[voting] themselves largess from the public treasury.” (Sir Alex Francis Tytler) Before the US, it was assumed such a system was impossible, and many of those who have tried to follow us have failed. It took nearly 5000 years of recorded history to get to a pluralistic government with voting rights to men and women of all races, and it took nearly as long as that to develop working capitalism (i.e. the creation of the middle class). So it’s difficult to argue that the lack of a successful example is proof of its impossibility. Those who made that argument 200 years ago were wrong and they’re still wrong today. If we only look to history, than the most successful and longest lasting societies were Imperial Dictatorships or Monarchies. That is not proof of their rightness.
We’ve definitely learned that just taking a hereditary hierarchy and replacing it with a dictatorial hierarchy (no matter how often we use the term “Comrade”) doesn’t work. You have to change the underlying culture. The bigger question in my mind is whether a democratic communist state could rise successfully without also being extreme nationalist. To avoid that, the citizens would likely need to extend the concept of family to all humanity rather than just to their compatriots. That’s an even further step but I still think it is within human grasp. In my opinion, the successes and failures of Mahatma Gandhi are worthy study in answering that question, and I highly recommend a study of Satyagraha and its impact on the independence of India in understanding how things so-called counter to human nature can be accomplished and what the challenges are. While I am unable to agree with many of Gandhi’s philosophies, particularly related to Ahisma, his use of Soul Force to change an entire culture is a worthy case study.
As I’ve said before, while we struggle towards that next step (I hesitate to call it an “ideal”), our current highly-regulated capitalistic republic with strong socialist influences does do a respectable job, and I would argue that it’s the best of any government system to date. I just don’t beleive that it’s the final step in the evolution of government systems, and when it is replaced it will seem in retrospect as barbaric as monarchies seem to us today.