A sociologist argues that the capitalist ruling class is willing to tolerate high rates of illegal immigration because these immigrants serve as a cheap labor pool. This sociologist is most likely drawing upon

This sociologist is most likely drawing upon: exploitation.

Explanation:

Exploitation is a well known reality that works in a economyc system where few people have money and power and they to pay vary bad salaries to their employees, under not very good working conditions. Exploitation is a old social problem which is still happening now a days.