By the 1950s, an upper class with consciousness of itself as such existed in the US. At the top of this class was a national elite. Since money was the only real criterion for admission to this class, it is distinguished from a traditional aristocracy. The formation and historical development of this class dates to the early days of the republic. The nationalization of the class is new, but its existence and awareness of it are not. In the mid-20th century, local elites were displaced by a national one. Power and relevance demanded entrance onto a national stage.

Prior to the Civil War, "old" families with wealth accumulated over generations comprised the upper class. In the aftermath of the Civil War, the era of industrialization saw the creation of newly enriched individuals with enormous amounts of money, such as Cornelius Vanderbilt. Efforts such as creating a list of the "Metropolitan 400" families in New York to exclude the newly rich from high society failed. Those with new money joined high society and became one with this class. In his study of the richest people living in the US since the Civil War, Mills documents the increasing percentage of the top class who originate there.