Cox: Electoral rules and electoral coordination

Cox. 1999. Electoral rules and electoral coordination. ARPS (2):145-61.

In Brief

Electoral coordination occurs at two levels: (a) at the district level and (b) at the national level. We know quite a bit about (a) (see Cox 1997), but far less about (b). (There is also a third level: coordination to distribute porfolios (in the cabinet or committee chairmanships), but Cox decides not to discuss that.)

COUNTING THE NUMBER OF PARTIES AND MEASURING LINKAGE:

These are all based on ENPP:

• District level: Use ENPavg, the average ENP in each district (measure by district)
• National level: Use ENPnat, the national ENP.

To measure linkage (b), use an inflation factor to measure how much higher ENPnat is than ENPavg. If I = 10, then about 10% of the size of ENPnat can be attributed to poor linkage (i.e. localized parties). Perfect linkage would have I = 0:

• I ("eye") = 100*(ENPnat - ENPavg) / ENPnat

(a) THE DISTRICT LEVEL: Two distinct M+1 rules.

STRATEGIC ENTRY:

This is where most of the action is: Parties, factions, and groups must decide who will run candidates--and how many each faction will run. They will coordinate in a Duvergerian manner (using Cox's M+1 rule) when three conditions hold (illustrated in a first-past-the-post district, but true elsewhere):

1. Everyone agrees that only two (M+1) parties have a realistic chance of winning. If we think that an extra party has a good chance, then there will be too many candidates.
2. Everyone agrees about which parties have the most realistic chances of winning.
3. We have short-term, instrumental preferences. If one party is trying to develop itself over the long term, it might run even if it knows it can't win right now.

• Examples: Studies of Japan (LDP learned not to overnominate), Chile (Concertacion).

STRATEGIC VOTING:

If parties don't regulate entry (i.e. they overnominate), then voters are likely to channel their votes primarily to the top candidates using the M+1 rule. Assumes that voters are instrumental and interested in short-term victories.

(b) THE NATIONAL LEVEL: LINKAGE

Use "I" (inflation factor--see above) to measure degree of each state's linkage. Linkage (Y) varies in response to two variables:

• X1: Upper tiers or vote distribution requirements. Incentives for linkage are stronger if you are trying to win in an at-large district (an upper-tier) that is bigger than the rest of the districts, or if votes must be dispersed geographically for a party's presidential candidate to win.
• X2: Centralization of power (unicameral, parliamentary, and unitary are more centralized than bicameral, presidential, and federal). When power is centralized, the incentives to coordinate are higher--since you have more to gain from doing so. (When there are more ways to get veto power--i.e. bicameral, presidential, and federal--it is less necessary to win everything nationwide in order to defend your interests.) See also Hicken 2005.

Evidence for X1 and X2:

• India and the USA: See Chhibber and Kollman (1998), who demonstrate a correlation between level of centralization and linkage.
• Brazil: Samuels (1998) notes as a side point that Brazil's decentralized government (lots of power for local states) prevents parties from linking together (evidence for X2).
• Possible X3: Social cleavages. Social cleavages can prevent coordination at both (a) and (b) if they are salient enough. See Ferree (2005) and maybe Lipset and Rokkan.
• Thailand: Institutional changes made linkage happen (Hicken 2005).