I was listening to a podcast of Quirks and Quarks yesterday that featured an interview of political scientist James Fowler on his recent work showing that the likelihood to vote was partially genetic. (Fowler is the same person who recently argued in New England Journal of Medicine paper that obese people tend to have obese friends.) The likelihood that genes may play a role in politics has come up before most notably in a paper by John Alford, Carolyn Funk and John Hibbing in 2005 that argued that political leanings are heritable. That study looked at identical and fraternal twins and found that the heritability of political ideology was about 50%. The work didn't say that genes could predict party affiliation just how a person stood on the left-right divide on a number of issues. Fowler hypothesized that the reason politics has a genetic basis is that back in our hunter-gatherer days, figuring out how to divide the spoils of a hunt would be important to the survival of the troop.
Following Fowler, I can imagine how early humans could take two approaches to how to divide up a downed mastodon. The paleo-leftists would argue that the meat should be shared equally among everyone in the tribe. The rightwingers would argue that each tribe member's share should be based solely on how much they contributed to that hunt. My guess is that any ancient group that had approximately equal representation of these two opposing views would outcompete groups that had unanimous agreement of either viewpoint. In the rightwing society, the weaker members of the group simply wouldn't eat as much and hence would have a lesser chance of survival reducing the population and diversity of the group. The result may be a group of excellent hunters but perhaps they won't be so good at adapting to changing circumstances. Now in the proto-socialist group, the incentive to go out and hunt would be reduced since everyone would eat no matter what. This might make hunts less frequent and again weaken the group. The group with political tension may compromise on a solution where everyone gets some share of the spoils but there would be incentives or peer pressure to contribute. This may be why genes for left and right leanings have both persisted.
If this is true, then it would imply that we may always have political disagreement and the pendulum will continuously swing back and forth between left and right. However, this doesn't imply that progress can't take place. No one in a modern society tolerates slavery even though that was the central debate a hundred and fifty years ago. Hence, progress is made by moving the center and arguments between the left and the right lead to fluctuations around this center. A shrewd politician can take advantage of this fact by focusing on how to frame an issue instead of trying to win an argument. If she can create a situation where two sides argue about a tangential matter to the pertinent issue than the goal can still be achieved. For example, suppose a policy maker wanted to do something global warming. Then the strategy should not be to go out and try to convince people on what to do. Instead, it may be better to find a person on the opposite political spectrum (who also wants to do something about global warming) and then stage debates on their policy differences. One side could argue for strict regulations and the other could argue for tax incentives. They then achieve their aim by getting the country to take sides on how to deal with global warming, instead of arguing about whether or not it exists.