Ideas are flying left and right for changing the constitutional system. I’ll get to them at some point, but right now those proposals are so vague that I can’t analyze them. Instead, let’s look at a much more mature proposal, the one to change the electoral system to a Mixed Member Proportional (MMP) system.
First, let’s review some vocabulary. A mixed member system combines two types of electoral formulae. In one tier, voters can vote for individual candidates. This is called the “nominal tier,” since you usually vote for a particular name. In most mixed systems, the nominal tier employs single seat districts. In the other tier, voters select a party, and parties designate individuals to sit in any seat that the party wins. This tier almost always uses some sort of party list, so it is called the “list tier.”
There are two major types of mixed member systems. In Mixed Member Majoritarian (MMM) systems (in Chinese often labeled 兩票並立制) the tiers are unlinked, so what happens in one has no effect on how the seats are handed out in the other. Taiwan, Japan, and Korea all have MMM systems. To illustrate, imagine a country with 200 total seats, half in each tier. There are four parties who win 40%, 30%, 20%, and 10% of the votes respectively.
|District seats (A)||76||22||2||0|
|List seats (B)||40||30||20||10|
|Total seats (A+B)||116||52||22||10|
Since Party A is the most popular party, let’s imagine that it will win most (76) of the district seats, Party B will win most of the rest (22), and Party C will win the remaining two seats. In the list tier, the seats are distributed to each party proportionally according to the list vote. The overall seat distribution is simply the sum of the two tiers. In this example, Party A wins a clear majority of the overall seats even though it won far less than 50% of the votes. This is what we call a manufactured majority, and it is quite possible in MMM systems. (The KMT holds a manufactured majority right now; it did not get 50% of the votes in either tier in 2012.) This is why the system is labeled with the third M, “majoritarian.”
The other flavor of mixed member systems is called Mixed Member Proportional (MMP; in Chinese usually called 兩票聯立制). In MMP, the two tiers are linked. The list tier vote is much more important than the nominal tier vote, as the party vote determines the overall seat share. Using the same example from above, the seats are distributed as follows:
|Total seats (A)||80||60||40||20|
|District seats (B)||76||22||2||0|
|List seats (A-B)||4||38||38||20|
Start by looking at the party list votes. Since Party A got 40% of the list tier votes, it will get 40% of the total seats, or 80 total seats. In the nominal tier, Party A has won 76 seats, so in order to get to a total of 80, it needs an additional 4 seats. Note that Party A gets the most party list votes, but it actually gets the fewest party list seats. Under the MMP logic, winning more districts doesn’t help a party win more total seats, it only changes which people get to sit in those seats. If Party A had won a 77th seat by beating one of the Party C district winners, it would have only won three list seats. Party C would have then gotten a 39th list seat. Either way, Party A gets 40% of the total seats and Party C gets 20%.
So the biggest difference between MMM (Taiwan’s current system) and MMP (which Tsai Ing-wen is promoting) is that MMM has majoritarian tendencies because the tiers are independent while MMP is proportional because the tiers are linked.
There are lots of arguments to be made for why MMP is better. My personal opinion is that just about anything other than a straight American-style single seat plurality system would be better than Taiwan’s current MMM system. However, I’m not going to go into these arguments right now. What I want to look at now are the arguments for why MMP won’t work. The concern is not that MMP will produce bad politics, but rather that, if we are not careful, MMP could simply self-destruct. Most of these concerns center around “overhang seats.”
Go back to the previous example. What if, instead of winning 76 district seats, Party A had won 82? Its 40% list share vote only entitles it to 80 seats, so perhaps it should get -2 list seats! What the Germans and most other countries using MMP do is to create overhang seats.
|Total earned seats (A)||80||60||40||20||200|
|District seats (B)||82||16||2||0||100|
|List seats (A-B)||0||44||38||20||102|
Party A is allowed to keep all 82 of its district seats, and it does not get any list seats. Party B is supposed to get 60 total seats, so it gets an additional 44 list seats. Likewise, Party C gets 38 list seats, and Party D gets 20 list seats. You will notice that this makes 102 list seats. The total chamber is thus enlarged. Instead of 200 members, there are now 202 members. Because of the overhang seats, Party A has a slightly larger seat share than vote share, while the other three parties are slightly underrepresented.
This may not seem so serious, but Germans think it is. In Germany, overhang seats have caused the parliament to expand by as many as 29 seats or about 5% of the total chamber (if my memory is correct). In Taiwan, we are used to the idea that a party’s seat share and vote share might be a little off, but Germans take the principle of proportionality much more seriously. In fact, the German constitutional court has ruled the current system is unconstitutional since it can produce such disproportional outcomes, and it has demanded that the overhang system be revamped. They haven’t finalized how they will reform the system, but one possibility is to expand the seats going to the other parties as well. In the above example, Party B might also get two more seats, and Parties C and D might each get one more seat. Thus, instead of having 202 seats, the two overhang seats might require a chamber with 206 total seats. With a lot of overhang seats, the chamber size might spiral out of control.
If this were the main problem, I wouldn’t be too worried. Taiwan has historically been willing to put up with modest amounts of disproportionality. Moreover, the modest disproportionality from a few overhang seats would be less than the average disproportionality incurred under either the current MMM system or the former SNTV system. Moreover, as long as the list tier is expanded from the current 30% of all seats to closer to 50% of all seats, we shouldn’t expect to see too many overhangs. The main reason Germany has overhang seats is that they have party lists in each state rather than one national list. If Taiwan had one list for Taipei City, the KMT might easily sweep all the district seats with less than 50% of the party vote (especially with revitalized PFP and New Parties), thus creating the potential for overhang seats. However, with a national list, the KMT’s overrepresentation in the north is balanced out by their underrepresentation in the south, so overhang seats are unlikely. (The 2008 sweep would have been just shy of requiring overhang seats.)
However, what if the KMT or DPP cynically set out to create overhang seats? Could they crash the system? Let’s go back to the first MMP example, where Party A won 76 district seats and only 4 list seats. What if Party A decided that 4 list seats wasn’t enough for their 40% list votes? What they could do is to form a fake party called Party A*. All of the district candidates would run under the Party A* label, and all of the list candidates would run under the Party A label. Now let’s look at the table:
|Total earned seats (A)||80||0||60||40||20||200|
|District seats (B)||0||76||22||2||0||100|
|List seats (A-B)||80||0||38||38||20||176|
Since Parties A and A* are legally unrelated, Party A gets a full 80 list seats to reflect its 40% party list vote share, while Party A* gets to keep all of its 76 district seats as overhang seats. Of course, they are actually the same party, and instead of 40% of the total seats, they have managed to win 56.6% of the total seats. Well now, that’s quite a difference.
Of course, if Party A did this, Party B would respond with a fake Party B* and so on. The logical result is that the MMP system of 100 nominal tier and 100 list tier seats would be transformed into a de facto MMM system with 100 nominal tier and 200 list tier seats. If we change the constitution to replace MMM with MMP, we probably don’t want to end up back with MMM. Moreover, it would be dishonest MMM, all the parties would snipe at each other for refusing to honor the rules of the game, the general public would think even less of politicians’ sense of fair play, and satisfaction with the way democracy works would probably sink even lower.
Would the parties really do this? In Italy, they actually have. About a decade ago, both of the major alliances came up with fake party lists precisely to avoid having success in the nominal tier count against the list tier. Not coincidentally, Italy recently discarded its mixed member system altogether. Germans have also recently become aware of what they call “negative voting,” though they haven’t yet been cynical enough to present fake party lists. (Insert your own joke about rule abiding German culture and corrupt Italian cultures here.) I have a hard time believing that the largest party in Taiwan would see an opportunity to turn a mere plurality in the legislature into a majority and wouldn’t seize it. If Taiwan does opt for a MMP system, there needs to be some way to prevent the fake list problem. I’m not quite sure how to do this without causing all sorts of other problems.
This brings us to the second serious problem. If you do find some way to ensure that all of a party’s candidates actually use the party’s label, what do you do about independents? Consider Yen Ching-piao 顏清標. Because of Yen’s background with organized crime, he and the KMT have decided that it is better for him not to officially join the party. In the past two elections, the KMT simply didn’t nominate a candidate in his district, and Yen won as an independent. He isn’t the only one. Both the KMT and DPP have found it useful at various times to defer to independents. However, these arrangements essentially take us back to the previous problem. Any seat won by an independent will, by definition, result in overhang seats. As such, if you allow independents, the KMT and DPP have an incentive to encourage their members to run as independents (or at least not to force allies to join their party). One solution is to not allow independent candidates. In Bolivia, all candidates must represent a party, and every party must nominate a candidate for every office. I don’t think this is a plausible arrangement for Taiwan. There is a very strong tradition of independents going back to the authoritarian era. Many people consider the option to quit their party and take their candidacy directly to the people to be a basic democratic right. Again, I’m not quite sure how to square this circle.
MMP could work in Taiwan, but the details matter. If reformers ignore potential abuses, they might be burying a time bomb right in the heart of the democratic system. I’m actually starting to think that these problems are sufficiently serious that we should consider a different electoral system, such as the old SNTV system or some version of Open List PR.