SELECTED LAWS AND COURT DECISIONS RELATED TO A FREE PRESS
(The full text of each law or court decision is available at the Web site listed beneath the description.)
Alien and Sedition Acts (1798)
This set of four acts passed by the Federalist Party, led by President John Adams, made it illegal for anyone to publish anything that might "defame" the government. The acts were declared illegal by Thomas Jefferson in 1801 during his term as president. See especially the Sedition Act, Section 2:
http://www.loc.gov/rr/program/bib/ourdocs/Alien.html
Espionage Act (1917)
Passed during World War I, the act made it illegal to obtain or share information that might interfere with the success of the armed forces or attempts to defend the country. The Sedition Act (passed in 1918 as an extension of the Espionage Act and not to be confused with the 1798 version) made it illegal to speak out against the government. It was repealed in 1921:
http://www.firstworldwar.com/source/espionageact.htm
Freedom of Information Act (1966)
This spells out what kinds of government documents must be made available to the public and under what circumstances documents can be withheld or redacted:
http://www.law.cornell.edu/uscode/uscode05/usc_sec_05_00000552----000-.html
New York Times Co. v. United States (1971)
The Supreme Court found that the U.S. government did not have the right of prior restraint to keep the newspaper from publishing the Pentagon Papers:
http://caselaw.lp.findlaw.com/scripts/getcase.pl?court=us&vol=403&invol=713
Branzburg v. Hayes (1972)
The Supreme Court found that "reporter's privilege" does not exist, i.e., reporters do not have an inherent constitutional right to keep sources confidential:
http://www.oyez.org/cases/case/?case=1970-1979/1971/1971_70_85