In the communist manifesto, karl marx hypothesized that capitalism would fail if workers

...if  workers united and revolted.

Explanation:

In the Communist Manifesto, Marx and Engels incite the workers of Europe to unite under the flag of communism —since they have nothing else to lose and everything to achieve— in order to revolt against unjust working and living conditions, seize the means of production, production, and capital away from landowners and capitalists, and equally redistribute them amongst the proletariat (the workers).  

labor leaders and organizations had the power to demand it.

explanation:

workers got a five-day workweek because the bcea protects and respect the rights of the employees. labor leaders and other groups demanded it.

i also think he is correct. i believe they came to washington to protest their rights.