Final answer:
John Stuart Mill's principle of utility impacts political modern legal thought by emphasizing action outcomes in terms of happiness and overall well-being while advocating for individual freedoms within the harm principle.
Step-by-step explanation:
John Stuart Mill's principle of utility posits that actions are right as they tend to promote happiness and wrong as they tend to produce the opposite of happiness. This utilitarian ethic emphasizes consequences over inherent rights or ethical sentiments. In the scope of political modern legal thought, Mill's principle serves as a critical foundation. By underlining the importance of the outcomes of actions and how they contribute to the overall well-being, this approach becomes influential in various applications ranging from legislation to economic policies. The principle is often invoked when debating laws and regulations, especially those that seek to balance individual freedoms with the greater good of society. Mill's harm principle further elucidates this by suggesting that individuals should have the freedom to act as they wish, so long as they do not harm others, thus providing a basis for liberal thought in modern legal systems.