Why was the armistice not resolved in 1951?

The armistice negotiations in the Korean War were not resolved in 1951 primarily due to disagreements over prisoner repatriation and the political status of Korea. The United States and its allies insisted on the repatriation of prisoners who did not wish to return to their home countries, while North Korea and China demanded their return. Additionally, issues surrounding the establishment of a lasting peace and the future governance of Korea complicated discussions, leading to a stalemate that lasted until the armistice was finally signed in 1953.