askchapo

Just as at first the capitalist is relieved from actual labour so soon as his capital has reached that minimum amount with which capitalist production, as such, begins, so now, he hands over the work of direct and constant supervision of the individual workmen, and groups of workmen, to a special kind of wage-labourer. An industrial army of workmen, under the command of a capitalist, requires, like a real army, officers (managers), and sergeants (foremen, overlookers), who, while the work is being done, command in the name of the capitalist. The work of supervision becomes their established and exclusive function.
https://www.marxists.org/archive/marx/works/1867-c1/ch13.htm

In Chapter 13 of Capital, Marx compares the functions of a security guard to being "like a real army". While the quote gives managers, foremen, and overlookers as examples, a security guard also fits. A security guard is also someone who is under the command of the capitalist and supervises the capitalist mode of production as their "established and exclusive function".

In 2004, the Department of Economic at the University of Massachusetts published an essay which coined the term "Guard Labor", written by Professor Samuel Bowles and Assistant Professor Arjun Jayadev. The essay is written in reference to the prior quote from Chapter 13 of Capital.

https://scholarworks.umass.edu/econ_workingpaper/63/

We will see that a significant portion of an economy‘s productive potential may be devoted to the exercise of power and to the perpetuation of social relationships of domination and subordination. We then measure these resources in labor units using the concept of guard labor, finding it to be a significant fraction of the U.S. labor force. Turning to evidence from other economies, we document substantial country-differences in the extent of guard labor and a strong statistical association between the extent of income inequality and the fraction of the labor force that is constituted by guard labor.

Nonetheless it may be of interest to count the fraction of the labor force occupying the roles of guard labor identified in the model: supervisory labor, private guards, police, judicial and prison employees, military and civilian employees of the department of defense (and those producing military equipment), the unemployed, and prisoners.

The essay makes the point that security guards and police are both part of the larger group, guard labor, which serves to "sustaining the status quo distribution of property rights". The essay also finds that economies with higher percentages of guard labor are also associated with higher levels of economic inequality.