One reason that Tsar Alexander II emancipated the serfs: a minister of his, Miliutin, pointed out that serfdom interfered with the making and maintenance of a good military. Russia's army was too big to support, yet too small to really respond to its defense needs (remember that this was just after Russia ran home with its tail between its legs at the Crimean War). So, it needed a small army with a large reserve corps. But training serfs and then sending them back to the villages would facilitate peasant unrest. The solution: end serfdom.

As I go through the lecture notes, I see that Professor Zelnik warned us that every year, at least one person says on the final that this is the reason for emancipation, and writes one sweeping answer that disregards all other explanations (e.g., the need to industrialise). Got it. Glad I caught myself.