Jefferson became president in 1801 after defeating John Adams, showing the peaceful transfer of power between political parties. As president, Jefferson reduced the size of government by paying off debts, cutting spending and taxes. However, he expanded the country through the Louisiana Purchase, doubling the size of the US. Tensions grew with Britain over attacks on American ships and impressment of sailors, leading to the ineffective Embargo Act of 1807. Jefferson left office having established Republican policies but also growing the power of the federal government, including establishing judicial review.