The early American republic underwent significant political and territorial changes during Period 4 APUSH, marked by the rise of political parties and westward expansion.
Thomas Jefferson's presidency brought transformative changes through the Louisiana Purchase, which doubled the size of the United States in 1803. When Napoleon decided to sell the territory for $15 million, Jefferson seized this opportunity despite his strict constructionist views of the Constitution. The Louisiana Purchase significance extended beyond mere territorial expansion - it secured American control of the Mississippi River, provided vast agricultural lands, and shaped America's destiny as a continental power. The purchase encompassed approximately 828,000 square miles, stretching from the Mississippi River to the Rocky Mountains, and from the Gulf of Mexico to Canada.
The period also saw the landmark Marbury v Madison decision in 1803, which established the principle of judicial review - the Supreme Court's power to declare laws unconstitutional. Chief Justice John Marshall's ruling in this case fundamentally shaped the American judicial system. The case arose from a dispute over judicial appointments between the outgoing Federalist administration and incoming Democratic-Republican Party under Jefferson. The Marbury v Madison significance lies in how it established the Supreme Court's role as the ultimate interpreter of the Constitution, creating a crucial check on both executive and legislative powers. This period witnessed the emergence of the first American political party system, with the Federalists advocating for a strong central government competing against Jefferson's Democratic-Republicans, who favored states' rights and limited federal power. These developments set the stage for American democracy's evolution and the country's territorial expansion throughout the 19th century.
