Aaron Burr began public service as an officer in the American Revolution, taking part in the expedition to Quebec and later serving in the Continental Army. He left military service in 1779 and built a successful legal practice in New York. Political work brought him into the state assembly and the office of state attorney general. Elected to the United States Senate in 1791, he served until 1797 and became a leading organizer of the emerging Democratic-Republican coalition in New York.

Burr helped establish the Manhattan Company in 1799. Its charter authorized a water-supply undertaking but also permitted banking activity, creating a financial institution that challenged established Federalist interests. Under the original presidential voting system, he and Thomas Jefferson received equal electoral totals. The House of Representatives selected Jefferson after prolonged balloting, making Burr vice president from 1801 to 1805.

He nevertheless gained respect for his conduct as presiding officer of the Senate, including during the impeachment trial of Justice Samuel Chase. Rejected as Jefferson's running mate in 1804, he sought the governorship of New York and lost. Conflict with Alexander Hamilton culminated in their duel at Weehawken on July 11, 1804. Hamilton died from his wound, and criminal proceedings and public hostility further damaged Burr's political prospects.

After leaving office, Burr traveled west and pursued ventures whose exact purposes remain debated. He discussed plans involving western territory and a possible expedition against Spanish possessions, while reports also alleged an intention to detach western states from the Union. General James Wilkinson, initially involved with him, denounced the activities to Jefferson. Burr was arrested and tried for treason in Richmond in 1807. Chief Justice John Marshall required evidence of the overt act specified by the Constitution, and the prosecution failed to secure conviction. Acquittal did not restore his public reputation.

Burr spent several years in Europe seeking support for new schemes before returning to New York in 1812 and resuming legal practice. He died in 1836. His career combined military service, legal skill, financial enterprise, and effective party organization with a fatal duel and an ambiguous western venture. The political accusations against him must be distinguished from the charges a court actually proved.