
1) Voting theory
Found on
https://www.crosswordclues.com/clue/spoilt-vote

In voting, a ballot is considered spoilt, spoiled, void, null, informal, or stray if election authorities declare it invalid and thus do not include it in the vote count. This may occur accidentally or deliberately. The total number of spoilt votes in a United States election has been called the residual vote. ==Types of spoiled vote == Ways of sp...
Found on
http://en.wikipedia.org/wiki/Spoilt_vote
No exact match found.