Contested elections

These generally involve either an administrative or a judicial process specified under state provisions whereby certain individuals (e.g., a voter, a group of voters, or candidates) initiate an action challenging an election on the basis of certain state-specified reasons that may include, for example, ineligibility of the person elected, illegal votes, fraud, or errors by election officials.

Source: ELECTIONS: The Nation’s Evolving Election System as Reflected in the November 2004 General Election, U.S. Government Accountability Office, https://www.gao.gov/assets/160/157713.pdf