On avoiding vote swapping

In this paper we analyse the problem of vote swapping in representative democracies. Vote swapping consists of exchanging votes between two voters from two different jurisdictions in order to beat a candidate that both voters dislike. The recent debates and legal disputes about this manipulation device raise some important ethical issues. We adopt an axiomatic approach, first establishing the relationship between vote swapping and a restricted form of gerrymandering, which is another way of manipulating elections in representative democracies. We then look for voting rules that are immune to such manipulations and show that any such voting rules only exist if either the voters or the candidates are given unreasonable power.