Madison's model of government is clearly planned out in the Constitution of the United States of America. Since the Constitution has become the framework for how the American government works now-a-days, it should not be a surprise that much of Madison's ideas are still reflected in America's government today. Madison's model of government established systems for separating power and checks and balances, which have helped to ensure America's government has lasted; however, no government is without problems and simply the streamlined ideas of Madison's government created issues right off the bat.
The systems for separating power that Madison depicted in the Constitution are still there today with little modification. The voters still elect the House of Representatives directly, the President is still elected by the electoral college, and the Supreme Court Justices are still appointed by the President with Senate approval. However, a major change since Madison's time is that people are less afraid of the self-interests of the majority now. In today's government, the senators are directly elected by the people instead of by the state legislatures. Such a change reflects the change in beliefs concerning factions. The preservation of property and wealth is still a big deal as it was in 1787, but today, people are have more trust that the system of the government will work, so interest groups form more readily and can even gin power in federal government to change such things as the election of senators.
After many years under the Constitution with the only main change being the addition of the Bill of Rights since many states found the Constitution too streamlined and would not ratify without some guarantee of rights, the change to the direct election of senators shows that the people had an issue with the separation of powers. The people wanted more power and, unlike in Madison's time, they were actually able to get the power they wanted through the process of constiutional amendments.
The idea of checks and balances in Madison's model government is also still seen today and may have even help up with less issues over the years than did the concept of separation of power. Today, there are still three branches of government and each branch still has a least one power to check another branch and one check on itself. For instance, the President can still veto bills that pass the Senate, but the Senate can still override that veto with a vote of over two-thirds for the bill. Also, the Supreme Court still has the power of judicial review as it was set up in the Marbury v. Madison case of 1803.
Therefore, although there have been 27 constitutional amendments and there are still problems with such things as the interpretation of the Constitution ("strict" or "loose"), the basic ideas of Madison's model government, which he framed in the Constitution are still being upheld today and can be seen in the government everyday.