Los braceros are physically powerful but socially powerless.
Los Braceros are people who come from Mexico specifically to work and then send money back home to Mexico. They will typically work on farms and in fields. As such, we know they are working, and we know they are physically able to perform the work required of farm/field hands. Because they are in a foreign land, however, they would have little to no say politically and socially. Thus, they are physically powerful but socially powerless, which is quite a contradiction however true it may be.