A recent diary was written about the failings of single-member districts in legislative bodies, using the UK general election as the example. The author, if I am recalling the intent correctly, favored multi-member districts elected on a proportional basis. Several variant election schemes were mentioned, but I'd like to highlight Mixed-Member Proportional Representation, commonly referred to as MMP.
There are benefits to having somebody to point to as "your" representative that you can work with on individual or community issues. Whether it's getting your unemployment benefits straightened out, getting the pothole in your street fixed, or advocating for the local college, it's good to have a legislator who is focused on the needs of your area. For that aspect of representation, I support either single member districts or very small (3-5) multi-member districts.
For the larger policy issues, though, the best way to ensure diversity of representation is to have a large multi-member district. This allows even small minority opinions the chance to be represented via proportional representation, if the number of seats is sufficiently large.
MMP offers the best of both worlds, by combining single-member district seats with a large (regional or state-wide) proportional district seated by some form of party list. Follow me below for an example.
For example, in the 2010 Assembly elections in California (the last ones before we went to Top Two), a little over 9.4 million votes were cast in 80 districts, of which Democrats received 54.3%, Republicans received 43.7%, Libertarians 1.2%, Greens 0.5%, Peace & Freedom 0.3%, and AIP 0.05%. However, Democrats won 52 of the 80 seats, or 65%, while the GOP won 28, or 35%. Arguably, Democrats are over-represented, Republicans are under-represented, and everyone else is shut out.
Let's say that the Assembly used a MMP system with a statewide list, 160 total seats, no arbitrary thresholds for representation, and the election results were exactly the same. Under MMP, the total allocation would be as follows:
Democrats 87
Republicans 70
Libertarians 2
Greens 1
Thus, in addition to their district seats, the Democrats would be allocated an additional 35 list seats and the GOP would get 42 list seats. All of the Libertarian and Green seats would come from the list. We've added two new perspectives to the legislature while preserving district elections.
What is left out of this analysis is that in 6 districts one of the two major parties failed to run a candidate, and none of the minor parties had anything close to a complete slate. With MMP, all of the parties would have greater incentive to compete everywhere, in hopes of driving up the statewide vote for their list if nothing else. Using the 2010 gubernatorial results instead as a proxy for statewide party support, the allocations would have been as follows:
Democrats 86
Republicans 65
AIP 3
Libertarians 2
Greens 2
Peace & Freedom 2
In this model, six parties are now represented with slightly greater progressive representation, while it would appear the GOP lost seats to the even more conservative AIP, which ran only one Assembly candidate, resulting in the poor statewide vote count in the first example.
Granted, I am over-simplifying matters somewhat. In most systems that use MMP, the parties must either win district seats (typically 1-5) or receive a minimum of 3-5% of the list vote to gain any seats, while the sample allocations are based strictly on percentages of the total vote. Also, in many MMP systems, voters cast two ballots: one for their district representative, and a second one for their preferred party list. Thus, for example, we might see somebody voting for the local Democratic candidate while voting for the Green Party list, or vice versa. While it is impossible to say with any certainty, it is certainly plausible that if two ballots were used, voters would largely choose Democrats or Republicans for their district, while voting for other choices with the party list vote.
While I don't think MMP could be adopted at the Federal level any time soon, it might well be a useful tool at the state level to ensure more representative legislatures. Something to consider, at any rate.