“Section 1983” refers to 42 U.S.C. §1983, the federal statute that enables you to file a civil action for deprivation of constitutional and federal statutory rights by persons acting under “color of law.” Originally enacted in 1871, Section 1983 litigation experienced a period of dormancy, until 1961 and the landmark Supreme Court case, Monroe v. Pape, 365 U.S. 167 (1961), which gave private litigants a federal court remedy as a first resort rather than only in default of (or after) state action.  Today, Section 1983 actions most commonly involve 1st Amendment issues like freedom of speech; 4th Amendment issues like search and seizure or use of force; 8th Amendment issues like cruel and unusual punishment; and 14th Amendment claims of due process violations.

 

http://cdn.ca9.uscourts.gov/datastore/uploads/guides/Section_1983_Outline_2012.pdf