Thomas Jefferson faced a lot of controversy with the transferring of power from Federalist John Adams. Jefferson allowed the Alien and Sedition Acts to end without renewal, he had the tax on liquor that caused the Whiskey Rebellion repealed and reduced government revenue leading Jefferson to cut costs by reducing the military, relayed instead on state militias.
The court case of Marbury v. Madison also took place and set up the Supreme Court's power to rule federal acts unconstitutional. In 1803, Jefferson purchased the Louisiana territory from France for $15 million - this was considered to be one of the most important acts during his administration. And in 1807, Jefferson ended the foreign slave trade and established the precedent of Executive Privilege. At the end of Jefferson's second term, he signed the Embargo Act of 1807.