Humans are capable of both extreme selfishness and great altruism. Government is one form of altruistic cooperation, but conservatives belittle it and try to destroy it.
Classical economic theory is woefully unable to explain many observed phenomena about economic behavior. But Complexity Theory, based on computer simulations, has been able to give convincing high level explanations for many economic phenomena, including cooperation.
Psychologists have done experiments to examine the basis of human cooperation. In one famous experiment volunteers are asked to play a game in pairs. During every round of the game, each person is paired up with someone else in the group. Each person can cooperate with the other person, or can decide to betray the other person. If both partners decide to cooperate, they both get, say, $10. If one person cooperates but the other person betrays the first person, then the first person gets nothing, but the other person gets $15. And vice verse. If both betray, then each gets only $5.
Using this basic setup, and varying the payoffs for the different outcomes, sociologists have gotten deep insight into the conditions under which humans cooperate. If others cooperate, then it makes sense for you to do so.
This experiment resembles the real world. It makes sense to cooperate with decent people who reciprocate. But only a saint or a fool would continue to cooperate with someone who repeatedly betrays them. Similarly, cooperation (e.g., in corporations and political parties and blogs) often vastly increases your effectiveness.
Interestingly, as long as you cooperte with some people you're not entirely screwed. If whites cooperate with whites, and blacks with blacks, and Asians with Asians, etc, then all can be quite comfortable. People in the in-group help each other and ignore or fight against people in the out-group. This is the way our ancestors probably lived in Africa: tribes fought other tribes.
So, human cooperation has a dark side. People tend to cooperate with people in the in-group (their religion, their race, their country, or their political party), but they tend not to cooperate with people in the out-group. This leads to conflict and war.
Conservatives often defend a libertarian notion of society. They're opposed to government, which they claim to be inefficient and corrupt and hopelessly naive, since cheaters (corrupt rich people or lazy nare-do-wells) will always ruin it. Conservatives prefer a market-based, distriubuted organization. Buchanan points out that such thinking can be taken too far. An extreme libertarian would oppose not only national governments, but also state governments, local governments, and even corporations. Indeed, some people hate working for a boss or being part of a company or bureaucracy. Such people prefer a world in which everyone looks after only themselves. For an extreme libertarian, all forms of human cooperation are doomed. What a depressing view of human nature!
But humans are designed to cooperate.
Cooperation benefits everyone, though there is a risk that cheaters will take advantage of the goodness of others and freeload. Society needs to discourage cheating. If too many people cheat, then the social contract breaks down and everyone suffers. That seems to be what's happening nowadays in America.
The book ends with a swipe at religion and a bow to Sam Harris' criticisms of religion. The atomistic, scientific view of humans that Buchanan favors is inconsistent with the religious view of humans as demi-gods embodying human form. While I largely agree with Buchanan's and Harris' criticisms of religion, I think he overstates the extent to which religious dogma determines public policy. Corrupt politicians exploit religious faith and fears to promote their views. The final chapter will unnecessarily alienate some religious people, who are, after all, progressives' natural allies in the fight against poverty and war.
As you can see, the book and this book review cover a lot of ground. Stimulating stuff!