Which factor is critical in evaluating the success of a military operation?

Evaluating the success of a military operation primarily hinges on whether the mission objectives have been achieved. This factor directly assesses the effectiveness of the operation in relation to its intended goals. If the primary objectives were met, it reflects that the operation was conducted efficiently and in alignment with strategic aims. Achieving mission objectives indicates that the operation was successful in accomplishing its purpose, whether that involves securing territory, disabling enemy capabilities, or achieving other specified aims.

While public perception, enemy casualties, and costs incurred can provide additional contexts for assessing an operation, they are secondary to the fulfillment of the mission’s objectives. Public perception might influence future operations or political support, enemy casualties can indicate operational impact, and costs can affect future decisions and resources, but they do not fundamentally determine the success of the military endeavor itself. Hence, focusing on mission objectives achieved is the most straightforward and reliable measure of a military operation's success.