There are lots of voting system criteria that have been described, but I have not seen this one - or any one like it - described before.
Bullet-voting prohibition Criterion: "A voting system should not be constructed in such a way so that it is both legal and rational for a voter to fill in a ballot with only one party or candidate name, so that the voter refuses to order by preference all candidates that are not his first preference." Since FPTP enforces bullet voting, it obviously fails the BVP criterion. In Approval voting, it is legal to vote for only one candidate, so it fails also. In score voting, it is legal to give 99 points to one candidate and 0 points to all others, so it also fails. All other voting systems (that I can think of right now) can be made compatible with this proposed BVP criterion by adding a rule that the voter must supply at least 4 (or whatever number sufficiently high) most preferred candidates, otherwise the vote is spoiled. Why do I consider the BVP criterion necessary? Two reasons: 1. It makes impossible some strategies that could otherwise be used by voters who are in favor of one of the top-2 parties, and want to ensure a two-party duopoly, even after the FPTP system is scrapped. I hold it for necessary that any change of the voting laws that scrap FPTP should not only mandate a better voting system, but also make it impossible for hidebound big-party voters to continue in their old mindset of "vote up my party, loathe the other big party, and pay no attention to any other party." 2. (Intertwined to reason #1) Elections shall, IMO, be occasions of public civics lessons. The voters should be forced to consider several different opinions, and no go reflexively party-list on every issue. By forcing voters to rank at least 4 alternatives, the voters would be forced to not only evaluate the other big party in relation to the minor parties, but also evaluate minor parties in relation to each other. That would force low-information voters to either throw away their vote, read up on policy positions, or random-rank their preferences #2 and below. So, what would happen if a voting system with a BVP-criterion enforcement would be introduced? I see two possible scenarios: 1. The big parties split into several very similar parties, so that hidebound voters of that party can vote a complete list of only party members 2. The big parties do not split, and the voters of those parties engage in mutual burying. Their voters vote their party #1, then supply a long list of minor parties, so that they do not have to give any help to the hated other big party. Meanwhile, many 3rd party voters will vote one big party at the bottom, and several will tactically vote both big parties at #1 and #2 from the bottom. In the first case, the big parties run a risk of the different daughter parties becoming entities of their own, that become difficult to control. That is a good thing. In the second case, the most centrist 3rd party will get a big boost, which is a good thing also. It is entirely possible that a new centrist party would be formed, peeling center-leaning voters off both present big parties. Then those big parties would become smaller, and with a much smaller span of political opinions within them, they would be more cohesive and we would get fewer intramural fights. All good IMO. Peter Gustafsson ---- Election-Methods mailing list - see http://electorama.com/em for list info
