Approval voting is an electoral system in which voters can select many candidates instead of selecting only one candidate.
Approval voting ballots show a list of all the candidates running and each voter indicates support for as many candidates as they see fit. Final tallies show how many votes each candidate received, and the winner is the candidate with the most support.
Approval voting advocates Steven Brams and Dudley R. Herschbach predict that Approval should increase voter participation, prevent minor-party candidates from being spoilers, and reduce negative campaigning. One study showed that Approval would not have chosen the same two winners as plurality voting (Chirac and Le Pen) in the first round of the 2002 French presidential election; it instead would have chosen Chirac and Jospin as the top two candidates to proceed to the runoff.
Le Pen lost by an overwhelming margin in the runoff, 82.2% to 17.8%, a sign that the true top two candidates had not been found. In the approval voting survey primary, Chirac took first place with 36.7%, compared to Jospin at 32.9%. Le Pen, in that study, received 25.1% and so would not have made the cut to the second round. In the real primary election, the top three were Chirac, 19.9%, Le Pen, 16.9%, and Jospin, 16.2%. A study of various "evaluative voting" methods (Approval and score voting) during the 2012 French presidential election showed that "unifying" candidates tended to do better, and polarizing candidates did worse, as compared to under plurality voting.
A generalized version of the Burr dilemma applies to Approval when two candidates are appealing to the same subset of voters. Although Approval differs from the voting system used in the Burr dilemma, Approval can still leave candidates and voters with the generalized dilemma of whether to compete or cooperate. But, Approval satisfies the favorite betrayal criterion, which means that it is always safe for a voter to give their true favorite maximum support.