With apologies to New Zealanders’ somewhat complicated memory of Robert Muldoon, I am sticking to my “piggyback MPs” as a preferred term for members elected under MMP via an alternative threshold to the one based on party-list votes.
Here I want to address briefly the question of whether allowing an alternative threshold, by which a party qualifies for list seats through the winning of one (or more) district seats, is itself a problem in electoral-system design. I have been wanting to address this issue for some time, and some of my thoughts are anticipated by a comment left by Rob at the previous thread.
Up front, let me state that I see no problem with the principle of an alternative threshold. If mixed-member proportional systems are to have a chance of delivering on the “best of both worlds” promise, then one really should allow both worlds to coexist simultaneously. One of those worlds is one in which local concentrations of support for particular parties or candidates are able to attain representation. The other world is one in which only nationwide levels of support for particular parties are worthy of representation. Any one of us might prefer one conception of representation over the other, but MMP is explicitly designed to promote both.
Now, one might respond that one need not have the alternative threshold in oder to obtain both of these worlds. Parties could still exist to target one or a few district seats, and earn their representation that way, without being entitled to any list seats.* I concede that this is a perfectly valid argument, and it seems to be the position taken by the New Zealand Electoral Commission in its MMP Review. That is fine; they have thought much more about these issues, and the needs of New Zealand society, than I ever can do.
However, I think it is a perfectly valid “best of both worlds” provision to say that we want to give incentives to smaller parties to attract support outside their district-based strongholds, while still being able to win representation based on their regional concentration. A very small party may have supporters around the country, but be concentrated in one area. Voters outside the areas of strength have little reason to vote for the list of such a party if it won’t win seats; by the same token, voters in a single district where the party has local strength may have little reason to vote for the party if it lacks any chance to win further seats via list votes obtained elsewhere. (If one seat is expected to affect the balance of power, the second consideration vanishes, of course.)
It seems to me that the decision whether to abolish the alternative threshold should be made not on the basis of disliking particular parties that take advantage of it. (Search on “Key cup of tea” if you are unfamiliar with the debate.) Rather, it should be taken after considering what minimal size of party is considered optimal in a given country’s proportional system. (One can never squeeze out all one-seat parties, as they are at least a latent possibility in any system that has single-seat districts, including mixed-member PR, but one can eliminated the opportunity for such parties to exist to seek additional seats via the list.)
What is the optimal minimum size for parties that win more than just a given district (or two or more), but also win list seats? Continue reading