The record shows clearly that Madison was as committed a federalist as Hamilton both during and shortly after the Constitutional Convention; after all, the two collaborated on the Federalist Papers. Within two years of the ratification of the Constitution, however, Madison had become one of the leaders of the opposition. What happened?
Some historians attribute Madison’s change in position to Jefferson’s return from France. There may be something to that. I think the better explanation, however, is that Madison and Hamilton did not view the objectives of federalism in the same way. At the time of the Convention, Madison was particularly concerned about the behavior and excessive authority of state governments; he saw the federal government primarily as a check on them, not a power in its own right. Hamilton, on the other hand, believed in a dynamic central government similar to that of Great Britain, and did his best to make it a reality during his tenure as Secretary of the Treasury. When Madison realized what was happening, he recoiled, and the rest is history.