Why in the last third of the XIX century. some theorists of socialism took the path of reformism?

The path of transformation for liberals is the path of reforms, and by no means revolutions. The liberals put forward the demand for limiting the activities of the state by law and proclaimed the principle of separation of the three branches of power, which you know from the teachings of Locke and Montesquieu. Defending the principle of individual freedom, liberals applied it in solving social issues, arguing that everyone is responsible for their own well-being.
They said that the state must carry out reforms that can protect the poorest strata of the population and prevent revolutionary outbreaks, eliminate enmity between classes, and strive to achieve universal welfare. In contrast to the liberalism of the mid-19th century. the new liberals recognized for the government and parties the right to play a major role in resolving the contradictions existing in society.

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