According to the doctrine of laissez-faire, governments should intervene as little as possible in the running of the economy. They should simply set the rules and the legal framework in which businesses operate and stand back and allow market forces to work freely.
The downside of this approach, especially in late 19th and early 20th century America, was that workers went unprotected from the excesses of industrial capitalism. Without proper regulation or government control, businesses could get away with driving down or ignoring safety standards, leading to numerous work-related deaths and injuries. Workers could be routinely exploited by their employers, who could keep wages as low as possible—especially during a recession—safe in the knowledge that there were countless others willing to take their place.
Laissez-faire was consistent with a thoroughgoing hostility toward labor unions. The prevailing economic doctrine held that unions interfered with the operation of the free market in labor and that their activities should therefore be curtailed. With lack of protection from either the government or labor unions, workers often experienced shocking pay and conditions. This led to growing demands for change which, in due course, sounded the death knell for laissez-faire.