Over the past month, Mitt Romney has aggressively appealed to moderate voters. President Obama, for some reason, hasn’t. But, in what he thought was an off-the-record interview with The Des Moines Register, Obama laid out a pretty moderate agenda for his second term.

It occurred to me that this might be a good time to describe what being a moderate means.

First, let me describe what moderation is not. It is not just finding the midpoint between two opposing poles and opportunistically planting yourself there. Only people who know nothing about moderation think it means that.

Moderates start with a political vision, but they get it from history books, not philosophy books. That is, a moderate isn’t ultimately committed to an abstract idea. Instead, she has a deep reverence for the way people live in her country and the animating principle behind that way of life. In America, moderates revere the fact that we are a nation of immigrants dedicated to the American dream — committed to the idea that each person should be able to work hard and rise.

This animating principle doesn’t mean that all Americans think alike. It means that we have a tradition of conflict. Over the centuries, we have engaged in a series of long arguments around how to promote the American dream — arguments that pit equality against achievement, centralization against decentralization, order and community against liberty and individualism.