Miguel asks a good question about the extent to which mixed-member systems might encourage regionalism and thus discourage nationwide coalition-building. He was responding to an earlier (and since revised) planting of mine on Mexico, and offering lessons from the Bolivian experience. Regarding Bolivia, Miguel suggested that in 1997-2002 there appeared to be an emergence of separate regional party systems, similar to what appears to have happened in Mexico. He says:
I actually suspect this is a byproduct of MMP systems, since it encourages the localization of candidates (to win SSD seats) â€” which is part of my skepticism for MMP in new democracies, if it encourages regionalist splits & discourages nation-wide coalition-building.
First off, Mexico does not have MMP. But we might expect that MMM would have more localizing tendencies than MMP (because the districts actually matter to the overall outcome in terms of the balance of seats held by parties). Such tendencies could generate party systems that are distinct in different regions, possibly with two major parties in one region that are not the same two parties that are most competitive in some other region–national multipartism, regional bipartism.
Does MMP (or MMM) discourage nationwide coalition building and emphasize regionalism? As always in comparison of electoral systems, one needs to ask, relative to what? If the allocation of PR seats to parties is national (as it is in Mexico, though not Bolivia) then it obviously encourages parties to think nationally to a degree that a system of just single-seat districts would not. In Bolivia, it is possible that the adoption of MMP increased both personalism and localism because the antecedent electoral system was pure closed-list PR. In fact, on the interparty dimension–how seats are awarded to parties–Bolivia changed little. The old system was PR with each province as a self-contained multi-seat district. The new one is also PR, but of the MMP variety. There is no national allocation.
What there is, with the change, is a series of individual races by plurality. With MMP, that means a change primarily on the intraparty dimension, in that some legislators are being elected on their own “nominal” votes instead of by party ranking. As a result parties may care about the qualities of the candidates being nominated to a greater degree than on the lists, and those candidates might seek to develop personal connections to the districts.
So, should we expect MMP in Bolivia to be more localizing and personalizing than what went before? Probably, and because there is no provision for overhang seats (the addition of seats to compensate for some party’s getting more seats in the SSD competition than its proportional share entitles it to), there should be more premium on parties’ putting effort into the SSDs than if winning these had no impact on the partisan balance of the legislature. In other words, the MMP system provides some new incentives on both the interparty and intraparty dimensions for parties and candidates to exert effort in winning local races. Given that some parties may have an edge over others in any given geographic region either programmatically or in terms of the types of candidates they can recruit, then this should promote more “localization (to win SSD seats)” than the system that went before it.
As for the expectation that I allude to above that MMM would generate greater emphasis than MMP on the single-seat districts (and hence localization and at least local bi-polarization) the only problem with that is that while the rank order of the parties differs across Mexican states, in only a minority of the states is the third party far behind. So, Mexico would seem not to support the hypothesis that MMM (or mixed-member systems more generally) promote local 2-party politics.* The continued strength of the third party (whichever it may be) in districts that it has no chance to win, even under MMM, is partly a result of the single vote. That is, every party that hopes to win PR seats has a strong incentive to nominate 300 candidates, whether or not viable. Even with this consideration in mind, however, we have to ask what the mixed-member system adopted in Mexico is being compared to. Does it promote localization or nationalization, relative to what?
For Mexico, where at one time the system was all SSDs (and all dominated by one party), the addition of a nationwide PR allocation clearly has helped nationalize politics to a degree that could hardly have happened under a pure SSD system.
In assessing the impact of adopting MMP or MMM (or any other electoral system), we have to ask what variables are changing relative to the former system. And the different starting points, as much as the differences in the systems adopted, affect our expectations about whether mixed-member rules would increase or decrease the extent of regional electoral competition in any given polity.
* I realize that Miguel is responding to the original post, where I employed the “slip of the keyboard” and referred to regional two-party systems, when what I meant was simply that the second party is the PRI almost everywhere and thus local competition is usually PRD vs. PRI or PAN vs. PRI, but rarely what it was in the presidential election: PAN vs. PRD.