Approval Voting

Approval Voting is a system of voting designed to allow voters to vote for, or “approve” of, as many or as few candidates as they wish. In a single-member constituency, the candidate with the most votes wins, just as in first past the post (FPTP), with the difference being that the vote tally reflects the broadest overall approval rather than the plurality of voters who selected that candidate as their favourite. Approval Voting is technically the simplest example of a system, with the range of scores being limited to two choices: 0 (non-approval) or 1 (approval). Thus, it is also the simplest possible method of.

A 2011 survey of 22 prominent experts on voting procedures published by École Polytechnique gleaned their views on 18 different voting systems, and found that Approval Voting was endorsed by the most experts (68%), followed by Alternative Vote a.k.a. Instant Runoff Voting (45%), while FPTP – the voting system currently in use throughout the U.S. and the U.K. – came out rock-bottom with 0% of the experts endorsing it.

Like Instant Runoff Voting (IRV), Approval Voting is one of the foremost voting systems being suggested for implementation in the United States, with its main advocate being the (CES). Fargo in North Dakota became the first U.S. City to adopt the method for its mayoral elections in 2018, with 64% of the public supporting the change. In 2020, St. Louis in Missouri adopted a variant of Approval Voting for its municipal office votes.

Electoral reform advocates in the United States, however, are divided on which voting system is best: the Center for Range Voting is on board with Approval Voting but prefers full Range voting a.k.a. Score voting, the Equal Vote Coalition pushes, while  disagrees and endorses Ranked Choice Voting (RCV) instead — specifically IRV. Hopefully, these differences of opinion won't undermine their collective efforts to throw FPTP into the dustbin of history.

Approval Voting in its basic form is designed for single-member constituencies, but may be adapted into for multi-member constituencies (such as a Senate election).

The good

 * One of the main advantages of Approval Voting is that it completely eliminates the “spoiler” and “centre-squeeze” effects that can occur in FPTP and IRV respectively, and along with them, any incentive for the voter not to vote for their sincere favourite. An additional candidate entering the race can only change the outcome of the election by winning it, and voters can approve their favourite candidate without any concern that this might help the greater-of-two-evils win. In other words, the system fulfils the monotonicity, participation and no favourite betrayal criteria.
 * A result of this freedom to vote for one's sincere favourite candidate is that every candidate's true level of support is reflected in the results, creating accurate and meaningful data on the population's political views. Under FPTP (and to a lesser extent IRV), support for candidates other than the two front-runners is artificially suppressed due to voters' fear of the “spoiler” and “centre-squeeze” effects.
 * Approval Voting is much simpler to understand than IRV for voters used to FPTP, as it does not involve multiple rounds or concerns about preferences. Because of the simplicity of counting, the process that led to the outcome of an election would be more transparent for the voters.
 * Logistically, the system can be easily implemented on machines and ballot forms that were previously used for FPTP voting calculations, because the only change it requires is the allowance for voting for “one or more” candidates; this would save on the huge costs of designing and creating new machines.
 * The rate of spoilt or invalid ballots would be even lower than for FPTP elections, because the ballot would still be valid no matter how many candidates the voter marks. It would be almost impossible for a voter to unintentionally spoil their ballot through genuine ignorance.
 * The outcome of an election would provide valuable information on how popular a winning candidate is in absolute terms, with the winner's overall level of approval showing whether the voters adore them or simply dislike them the least. Neither the selection of a single candidate under FPTP, nor the ranking of candidates under IRV, provide any information on whether the voter actually likes or dislikes a candidate: all they can communicate is where the voter places the candidate relative to the other candidates.

Possible drawbacks
While Approval Voting is superior to FPTP in virtually every meaningful way, it has several features that may compare unfavourably with IRV, mainly due to the fact that it does not allow voters to differentiate between, or rank, candidates whom they may approve to varying degrees.
 * The voter is faced with the dilemma of where to define their “threshold of approval”: on one hand, approving of additional candidates beyond their favourite can sometimes undermine said favourite candidate's chances (in other words, failing the later-no-harm criterion), but on the other hand, withholding approval from non-favourite but tolerable candidates can hurt their chances against candidates whom the voter hates (and if everyone only approves their favourite, the system degenerates into FPTP.) This problem is variously known as Burr's dilemma or the chicken dilemma, and while it is a drawback, at least it does not undermine the voter's incentive for approving their sincere favourite candidate – only their second- or third-favourite. While the act of adding subsequent preferences cannot harm one's first preference under ranked voting methods such as IRV, it very much can help to elect someone whom the voter likes less than the candidate who would otherwise have won, which calls the value of the later-no-harm criterion into question.
 * The lack of candidate rankings on the ballot can also feasibly create situations where a “least-disliked” candidate is elected over one who is the favourite of a majority of voters.

Does it violate "one person, one vote"?
Absolutely not.  If a voter truly had more than one vote, this would mean they would be able to vote multiple times for their favourite candidate — something which Approval Voting obviously does not allow. Approving multiple candidates on the ballot does not mean having multiple votes: it means that the voter is casting a single vote that divides all the candidates into tiers of "approved" or "not approved". Essentially, FPTP has the voter enact the same division of candidates into two tiers, with the (quite arbitrary) added restriction that every candidate except one must be placed in the lower ("not approved") tier.

If anything, it is FPTP that undermines the "one person, one vote" principle, considering that a voter undoubtedly has opinions on all the candidates, but is only permitted to record one of those on the ballot — which means that the system could justifiably be described as "one person, a fraction of a vote". Furthermore, when FPTP elects a candidate with a plurality but a minority of votes, the majority of voters who voted against that candidate are left without a representative. These voters might have been okay with one or more of the other candidates who were not their first choice, but were not allowed to make this known on the ballot, so for them the system is effectively "one person, no vote".