Mexico 2021

The following was a comment by Manuel on a post about the 2018 election. It certainly deserves a more prominent planting hole, so I am copying it here. Please note the following is authored by Manuel Alvarez-Rivera of the always valuable Election Resources on the Internet, not by me.

Note Manuel’s very interesting observation that this time the system functioned as pure mixed-member majoritarian (MMM), i.e., with “parallel” allocation of the single-seat district and list components, rather than with any compensatory allocation.

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Preliminary results of the June 6, 2021 Chamber of Deputies election in Mexico indicate that no gaming of the 8% disparity cap took place this year, largely because the ruling “Juntos Hacemos Historia” (JHH; Together We Make History) coalition won fewer single-member mandates than in 2018.

With 99.6% of the tally sheets processed, Mexico’s Preliminary Election Results Program (PREP) reports the distribution of Chamber of Deputies single-member seats stands as follows:

PAN – 33
PRI – 11
PRD – 0
PVEM – 1
PT – 0
MC – 7
MORENA – 64
PES – 0
RSP – 0
FXM – 0
PAN-PRI-PRD – 65
PVEM-PT-MORENA – 119

The PAN-PRI-PRD “Va por México” (VPM) opposition coalition ran candidates in 219 of 300 Chamber districts, while JHH (PVEM-PT-MORENA) contested 183. On the basis of the coalition agreements published on the National Electoral Institute (INE) website, the party distribution of single-member seats would be as follows, with party single-member seat and vote shares in parentheses:

PAN – 72 (24.0%; 18.3%)
PRI – 30 (10.0%; 17.8%)
PRD – 7 (2.3%; 3.7%)
PVEM – 30 (10.0%; 5.5%)
PT – 31 (10.3%; 3.3%)
MC – 7 (2.3%; 7.0%)
MORENA – 123 (41.0%; 34.0%)
PES – 0 (0.0%; 2.7%)
RSP – 0 (0.0%; 1.8%)
FXM – 0 (0.0%; 2.5%)
Independents – 0 (0.0%; 0.1%)

The coalition seat and percentage totals, including votes and mandates won by their respective constituent parties running alone, are as follows:

PAN-PRI-PRD – 109 (36.3%; 39.7%)
PVEM-PT-MORENA – 184 (61.3%; 42.7%)

The absence of PVEM-PT-MORENA and PAN-PRI-PRD coalition candidates in many districts made little difference in the overall election outcome. Had both coalitions ran in all 300 districts, the MORENA-led coalition would have had a net loss of just four seats, gained by the PAN-led coalition.

Meanwhile, the official allocation of PR list seats won’t be known until as late as the third week of August, but on the basis of preliminary figures it would be as follows:

PAN – 41
PRI – 40
PRD – 8
PVEM – 12
PT – 7
MC – 16
MORENA – 76
PES – 0
RSP – 0
FXM – 0

Consequently, the overall composition of the Chamber of Deputies would be as follows (seat shares in parentheses):

PAN: 72 + 41 = 113 (22.6%)
PRI: 30 + 40 = 70 (14.0%)
PRD: 7 + 8 = 15 (3.0%)
PVEM: 30 + 12 = 42 (8.4%)
PT: 31 + 7 = 38 (7.6%)
MC: 7 + 16 = 23 (4.6%)
MORENA: 123 + 76 = 199 (39.8%)

Therefore, the coalitions would have the following totals:

PAN-PRI-PRD: 109 + 89 = 198 (39.6%)
PVEM-PT-MORENA: 184 + 95 = 279 (55.8%)

Since no party hit the 8% disparity cap, Mexico’s Chamber of Deputies electoral system operated in a purely parallel manner in this year’s election. Moreover, the JHH coalition parties won between themselves 47.76% of the “effective national vote” cast for parties entitled to take part in the allocation of PR seats. As such, the parties’ joint share of 55.8% of the Chamber seats happened to be just 8.04% above their effective national vote aggregate percentage. Had PR list seats been distributed among coalitions (as opposed to individual parties), the application of the 8% disparity cap would have reduced their overall seat total by only a single mandate.

Finally, the over-representation of the PVEM-PT-MORENA coalition in the Chamber of Deputies – where it retained a reduced but comfortable majority – stems largely from its continued dominance in twelve states in southern Mexico, where it won 85 of 99 single-member seats (85.9%) with 49.1% of the vote, while the PAN-PRI-PRD coalition trailed well behind with 32.9% of the vote and 14 seats (14.1%). In the rest of the country the election was closely fought, and while the VPM coalition parties won the popular vote, 43.5% to 39.2% for the JHH coalition partners, the latter still won slightly more district seats (99) than the former (95). Meanwhile, MC won all its seven district seats in Jalisco state, where it topped the poll with 31.5%, in a close three-way race with the PAN-PRI-PRD and PVEM-PT-MORENA coalitions, which polled 31.3% and 28.6%, respectively.