Anti-federalists had argued that one-year House terms would be more "democratic" or "representative" than longer terms. Defending the two-year terms adopted in the Constitution, Madison argues that Representatives in the House will need some knowledge of national affairs (how things work in the different states), as well as some minimal knowledge of foreign affairs. Because experience in the House counts here, two-year terms are appropriate.
Madison also argued that one-year House terms would increase the amount of election fraud in the election of Representatives. His reasoning was that it takes a while for election fraud to come to light. If the elections were annual, a representative could buy an election and serve most of his term before the fraud came to light.