This document summarizes key events from 1800 to 1812, including Thomas Jefferson's election as president, the Louisiana Purchase which doubled the size of the US, and the start of the War of 1812. The election of 1800 was controversial but resulted in the first transfer of power between political parties in American history. Jefferson took a more moderate and pragmatic approach as president compared to his previous positions. Tensions with Britain and France over trade and impressment of American sailors led to calls for war, and the War of 1812 began in 1812, though it was divisive with little national support.