Government Documents

Executive Branch

The White House official website
Speeches and other official documents of the current president and vice-president.

The White House website archive
Website and some components archived by the Wayback Machine beginning in December 27, 1996 to present. 

Legislative Branch

ProQuest Congressional
Comprehensive collection of congressional documents from 1789 to the present including hearings, testimony, House, and Senate publications.

U.S. Congressional Serial Set.
Searchable full-text reports and bills published from 1789-1980.

Congress.gov.
Official website for the Library of Congress.

House of Representatives
Official website for the U.S. House of Representatives

Senate
Official website for the U.S. Sentate

Judicial Branch

Nexis Uni
Federal Case Law, including full text of all Supreme Court decisions.

U.S. Supreme Court
Official website of the U.S. Supreme Court, includes recent U.S. court decisions and transcripts of oral arguments.

The Oyez Project: U.S. Supreme Court Multimedia Database. 
In addition to decisions, contains background information about justices and audio files of oral arguments.

U.S. Courts.
Links to U.S. courts of appeal, district courts, and bankruptcy courts. Includes map.