The Official Proposal and Eventual Compromise, Mechanics.
From Miguel at Ciao a careful and informed analysis of the voting proposal, and projections about where that would leave the assembly if voting patterns from the presidential election replicated themselves.
Evo's proposal is for three delegates to be elected from each of the country's 70 uninominal legislative districts (the single-seat district tier of the House of Deputies). That would allow for a constitutional assembly of 210 members. Such a proposal isn't radical, of course, although it does give preference to population (the legislative districts are roughly based on census figures) over other forms of representation (e.g. ethnic or territorial). Smaller departments (w/ fewer legislative districts) have already complained. As of today, Beni, Pando, and Tarija won't go, Chuquisaca hasn't decided, and Cochabamba, Santa Cruz, and Oruro oppose Evo's formula for a constitutional assembly. That's 7 of 9 departments opposed.
In large measure, the reaction against Evo's constitutional assembly plan comes from the electoral formula he wants. He wants the winning list in each district to win 2 seats; the second-place list would win 1 seat. Unless, of course, a list wins a simple majority (50%+1). In which case that list would win all three seats. Theoretically, a party could win 51% of the vote in every single district & win every single seat (leaving 49% of votes unrepresented).
If voters voted as they did in the 2005 election, by legislative district, MAS would win:
Chuquisaca 13 (of 18) seats
La Paz 41 (of 45) seats
Cochabamba 26 (of 30) seats
Oruro 10 (of 15) seats
Potosí 17 (of 24) seats
Tarija 3 (of 15) seats
Santa Cruz 13 (of 39) seats
Beni 0 (of 15) seats
Pando 0 (of 9) seats
This would give MAS 133 (of 210) seats, or 63.3% of the legislature (nearly two thirds). This is a highly disproportional result, when we consider that MAS only won 43.5% of the vote across the 70 legislative districts. How votes are translated into seats can have dramatic consequences.
This obviously caused an uproar among both the opposition and in the departments, starting with Santa Cruz.
So the compromise according to MABB, based on what has been reported, is set out like this
The CA bill calls for the election of 255 members, of which 210 will be elected with direct vote. There will be three members per electoral district. Two for the party, group, civic organization, ethnic group, etc., that wins the most votes and one for the second majority. The number of electoral disctricts is 70. That satisfies the demands of the government. The other 45 members will be elected in departmental districts. That means each department will have five more members. The first two seats will go to the winner and the rest three will be distributed to the political forces achieving 5% of the vote.
One thing to highlight is the mode of seat distribution in the first 210 members. Had the government gotten what it wanted, the three seats would have gone to the political force winning 50% plus of the vote. As you can see now, it will be distributed among the first and second majorities. This was an important victory for the opposition. Another important victory was that the CA will carry on to completely reform the constitution,
Now lets go back to Miguel at Ciao, and he runs a projection, again based on the results of the 2005 elections, but based on the new electoral formula:
La Paz would elect 50 delegates (45 from its 15 districts, 5 department-wide). MAS should expect to win each district, for 30 seats, plus another 2 department-wide seats, for a total of 32.
Cochabamba would elect 35 delegates (30+5). MAS should expect to win nine of ten districts & place second in the other, for 19 seats, plus another 2 department-wide seats, for a total of 21.
Santa Cruz would elect 44 delegates (39+5). MAS should expect to win in five districts & second in three others, for 13 seats, plus another 1 department-wide seat, for a total of 14.
Chuquisaca would elect 23 delegates (18+5). MAS should expect to win in five districts & second in the other, for 11 seats, plus another 2 department-wide seats, for a total of 13.
Oruro would elect 20 delegates (15+5). MAS should expect to win in three districts & second in the other two, for 8 seats, plus another 2 department-wide seats, for a total of 10.
Potosí would elect 29 delegates (24+5). MAS should expect to win in seven districts & second in the other, for 15 seats, plus another 2 department-wide seats, for a total of 17.
Tarija would elect 32 delegates (27+5). MAS should expect to win one district & second in two others, for 4 seats, plus another 1 department-wide seat, for a total of 5.
Beni would elect 20 delegates (15+5). MAS should expect to place second in one district, for 1 seat, plus another 1 seat department-wide, for a total of 2.
Pando would elect 14 delegates (9+5). MAS should expect to place second in one district, for 1 seat, plus another 1 seat department-wide, for a total of 2.
The grand total would give MAS 116 delegates, or 45% of the constituent assembly (based on 43.52% of the total nation-wide vote across uninominal districts).