So there's that change of general consciousness, and then there's this boom after the war, this expansion into the West. It was like the 1950s. The American economy was pumping at top speed. The kinds of people who would move into these communities and organize their lives around a utopian dream now had dreams about the West.

I was really interested in 20th century communalism and alternative communities, the boom of communes in the 60s and 70s. That led me back to the 19th century. I was shocked to find what I would describe as far more utopian ideas in the 19th century than in the 20th century. Not only were the ideas so extreme, but surprising people were adopting them.

They're people who probably imagine that they would have had a better time in the past. I wouldn't imagine you'd encounter a lot of black people saying 'Oh, the '50s, that was when America was great.' It's very dangerous because the past was imperfect, and you can't go back anyway.

The thought was, 'We're going to go to California, where the soil is black and ten feet deep, and there are no rocks, and there's gold in the hills.' The West becomes the surface onto which people project their fantasies, where once the future had been the place they projected their fantasies. So it's not just the war that ends the utopian communities, but what follows.

One of the things that's amazing about reading the private writing of these folks is that they enthusiastically describe things which we have now seen, and which are widely regarded as unappealing. They'll write, "It's going to be beautiful, we're going to have a town of 1,000 stone buildings that are all identical." And we as modern readers think, we've seen that; that's bad Soviet architecture or a public housing project. Nobody fantasizes about living there.

I worry that I may have overstated the impact of Civil War on the utopians. By the time the Civil War comes, most of the communities were quite separated from the wider American society. Their rhetoric is still about transforming the world, but they're not having that much traffic with their neighbors.

Because the utopian's worldview was framed around moving toward this perfected future, it helped stimulate the private exertions that add up to social progress. Progress is work. People need to build things and sacrifice and have a harder life for things to get better. On its own, I don't think even the most brilliant critique stimulates that kind of effort as well as an appealing vision of the future.