What is the theme in In the American Grain by William Carlos Williams?

The idea of “place” is significant in an understanding of national identity, but maybe more significant in the American identity than in that of some other nations. America will always be the New World and, as such, unformed, unsophisticated, more inclined to action than to thought. Many of its more interesting citizens will suffer for this, because, Williams believes, it is always easier to fit within an established framework than to forge a new path.