Adams's major accomplishment while in office was keeping America out of war with France. However, his policies on this matter also led to his downfall. His use of the Alien and Sedition Acts against his political opposition pushed the Republicans over the edge and was a huge part of the campaign against him in 1800.
When Adams became president, the French were regularly raiding American ships in the Atlantic. Adams sent ministers to try and stop this, but his ministers were rebuffed and three diplomats from France instead sent a letter asking for tribute of $250,000 in exchange for the meeting. Fearing that this posturing would eventually lead to war with France, Adams decided that the best course of action was to ask Congress to begin building up the military. The Democratic-Republicans balked against Adams's request. In response, Adams released the letter to the public replacing the names of the three French diplomats with the initials X, Y, and Z. A public uproar resulted forcing the Democratic-Republicans to change their stance. Trying to avert war, Adams quickly sent diplomats back to France who were able to come to an agreement and preserve the peace.
Alien and Sedition Acts
While America was preparing for a possible war with France, Congress passed the Alien and Sedition Acts. These measures were designed to limit immigration and free speech. Unfortunately, the acts were then used to suppress the political opponents of the Federalists, who were speaking out against the government's policies. Many were arrested and some newspapers were closed down. Jefferson and James Madison crafted the Kentucky and Virginia Resolutions in protest. While they did not really change the situation, they were used to sway public opinion against Adams.
No Second Term
Adams did not win a second term in office, most likely because he was opposed not only by Thomas Jefferson and the Democratic-Republicans but also by members of his own party including Alexander Hamilton. Thomas Pinckney again ran for vice president and Hamilton campaigned for him. Jefferson won the election.
Adams spent his last hours in office appointing Federalist judges and office holders based on the Judiciary Act of 1801. His goal was to fill posts with those he felt shared his views on the role of the national government. These were collectively given the title, “midnight appointments.” When Jefferson took over, he removed many of these people from office.