Consequences of hypothetical “cast one vote for OR against” system?
I've been reading about tactical voting - often it happens when a voter is more motivated to avoid one candidate than elect another. Tactical voting is considered a risk for many voting systems, or at least a manipulation of their original intent. I wonder what the consequences for voting behaviour would be if the option to express disapproval was made explicit.
What about if voters had a single vote which they could cast either for one candidate or against another, but not both? Sum them for each candidate and subtract the latter from the former, highest final score wins.
Has anybody made predictions, conducted simulations etc. on how mass voting behaviour would play out in such a system? Is there an obvious reason why I can't seem to Google such a system, whereas standard single non-transferable vote and disapproval vote (of which I am proposing a simple combination) have been much discussed? Is there something trivially 'wrong' with it? Am I right in thinking it could eliminate tactical voting?