This article on Samuel Bowles (worth reading in its entirety) discusses the figure:
Inequality leads to an excess of what Bowles calls “guard labor.” In a 2007 paper on the subject, he and co-author Arjun Jayadev, an assistant professor at the University of Massachusetts, make an astonishing claim: Roughly 1 in 4 Americans is employed to keep fellow citizens in line and protect private wealth from would-be Robin Hoods.
The job descriptions of guard labor range from “imposing work discipline”—think of the corporate IT spies who keep desk jockeys from slacking off online—to enforcing laws, like the officers in the Santa Fe Police Department paddy wagon parked outside of Walmart.
The greater the inequalities in a society, the more guard labor it requires, Bowles finds. This holds true among US states, with relatively unequal states like New Mexico employing a greater share of guard labor than relatively egalitarian states like Wisconsin.
