In "A Supermarket in California," Ginsberg offers a critique of the United States during the 1950s. His critique is similar to the one offered by other members of the Beat generation. He is sorry to see the way the country has changed, and he dislikes the consumerism and capitalism that controls America.
Towards the end of the poem, Ginsberg asks Whitman about the America of one hundred years ago. By ending the poem in this way, Ginsberg indicates that he longs to go back to an America that resembles the one Whitman loved and wrote about.