She argues that British colonizers saw their North American empire as a place to dump their human waste: the idle, indigent and criminal...
In the book’s most ingenious passages, Isenberg offers a catalog of the insulting terms well-off Americans used to denigrate their economic inferiors. In 17th-century Virginia, critics of rebellious indentured servants denounced them as society’s “offscourings,” a term for fecal matter. A hundred years later, elites railed against the “useless lubbers” of “Poor Carolina,” a place she calls the “first white trash colony.” In the early 19th century, landowners described the landless rural poor as boisterous, foolish “crackers” and idle, vagabond “squatters”...
By
 the second half of the 19th century and into the 20th, Isenberg shows, 
crude caricatures gave way to seemingly scientific explanations of 
lower-class status. “Class was congenital,” she writes, summarizing a 
mid-19th-century view of poor whites. One writer highlighted the 
“runtish forefathers” and “consumptive parents” who birthed a “notorious
 race” of inferior white people. Essayists described human differences 
by borrowing terminology from specialists in animal husbandry. Just as 
dogs could be distinguished by their breeds and horses distinguished 
from mules, so could people be characterized as superior or inferior 
based on their physical traits.
By
 the late 19th century, some writers used family genealogies to trace 
the roots of criminality, illness and insanity, and warn of the dangers 
of “degeneration.” By the early 20th century, armed with increasingly 
sophisticated statistical tools and new understandings of genetics, 
eugenicists offered the most chilling of responses to poor whites: They 
argued that the state should use its power to keep them from 
reproducing. Those arguments shaped one of the Supreme Court’s most 
notorious decisions, Buck v. Bell (1927), in which the court, with 
Justice Oliver Wendell Holmes writing for the majority, upheld a 
Virginia sterilization program to prevent “generations of imbeciles” 
from proliferating and thus to keep the nation from being “swamped with 
incompetence.”
The
 story of eugenics offers an example of the ways that, throughout the 
American past, questions of class status have been entangled with 
notions of racial inferiority. Isenberg makes a strong case that one of 
the most common ways of stigmatizing poor people was to question their 
racial identity. Backcountry vagabonds were often compared unfavorably 
with the “savage,” nomadic Indian. Sun-browned tenant farmers faced 
derision for their less-than-white appearance. After the emancipation of
 slaves, politicians warned of the rise of a “mongrel” nation, fearful 
that white bloodlines would be contaminated by blacks, a process that 
might expand the ranks of “trash” people.
(Sugrue also makes this critique of the book: "a history of class in America that assumes its whiteness and relegates 
the nonwhite poor to the backstage is one that misses the fundamental 
reality of economic inequality in American history, that race and class 
were — and are — fundamentally entwined.") 

 
