What legal principle was established in the Harlow vs Fitzgerald case?

The legal principle established in the Harlow vs Fitzgerald case is qualified immunity for law enforcement officers. This doctrine protects government officials, including law enforcement officers, from being held personally liable for constitutional violations—like the right to free speech—as long as the violated right was not "clearly established" at the time of the misconduct. In this case, the Supreme Court emphasized that officials should not face liability if they reasonably believed their actions were lawful, thereby allowing them to perform their duties without fear of constant legal repercussions. This principle is crucial in balancing the accountability of officials with the need to allow them to execute their responsibilities effectively.