This month there have been two presidential elections in the Americas under different rules requiring a second round (runoff) under certain conditions. In one, there will almost certainly not be a runoff, while in the other there may be. Yet in the one in which there probably will not be a runoff, the election was extremely close and a runoff could change the outcome. In the one where there may be a runoff, the leading candidate is far ahead, and a runoff almost certainly would be superfluous.
Results from Haiti’s February 6 election remain provisional, but Rene Preval is hovering right around half the votes. BBC (seen on PoliBlog) reports there might be a runoff, with Preval currently at 49.6% of the votes. This result is with 72% of the vote counted. The runner up, Leslie Manigat1, is at 11.6%.
In other words, in Haiti, there could be a runoff between a candidate who very narrowly missed a majority and a candidate trailing him by thirty eight percentage points. Why? Because the Haitian constitution mandates a runoff unless the leading candidate has at least one more than half the votes in the first round.
Meanwhile, Costa Ricans await the results of their presidential election, held the day before Haiti’s. The leading candidate, Oscar Arias SÃ¡nchez, has 40.5% of the votes, according to preliminary results posted by the Tribunal Supremo Electoral (via Adam Carr). The runner up, Otton SolÃs Fallas, has 40.3%. There will not be a runoff if this result holds, even though the leading candidate is nearly ten percentage points short of a majority and leads his main challenger by only two tenths of a percent (3,250 votes). Why? Because under the Costa Rican constitution, a runoff is held only if the winner of a plurality of the vote has less than 40%.
So, the Haitian first-round result is by any standard decisive, and if Preval really is that close to 50% there is almost no chance whatsoever that a runoff could lead to Preval’s defeat. But in Costa Rica, there is a very good chance that a runoff could produce a different result, but there will not be one (unless, of course, the recount puts both candidates below 40%).
There are better ways to determine when a plurality is sufficient and when there should be a top-two runoff. For instance, the double complement rule, first proposed in 1994 by Rein Taagepera and yours truly (in Comparative Political Studies). Under the DCR, in any election in which no candidate obtains over 50%+1, there is a runoff if (and only if) the second candidate’s shortfall from majority is less than double that of the leader.
In other words, if the leader has 44%, he is six percentage points short of 50%. There would be a runoff if the second-place candidate had more than 38%, which is double the leader’s shortfall from majority. If the second candidate is under 38%, the election is over in one round, with the leader’s 44% sufficing. Obviously, the gap required between the top two candidates to avoid a runoff shrinks as the leader approaches 50% and increases as the leading candidate’s plurality decreases–as it should. So with a leading candidate at 40%, there would be a runoff unless the second candidate had less than 30%.
The DCR is not actually used anywhere, but it was the inspiration behind the rule adopted in 1994 in Argentina when that country junked its US-style electoral college. The Argentine rule is a bit more complex. A leading candidate with 45% wins in one round under any circumstances, even if the runner-up is at 44.99%. And less than 40% for the first candidate necessitates a runoff no matter how far the runner-up trails. But in between 40% and 45%, the first round is decisive only if the leading candidate has a ten-percentage-point lead over the runner-up.
The spirit is the same as the DCR, in that the Argentine rule says that what matters is not so much the absolute share of the votes (unless it is over 50% of course), but how successful the leader is at building a majority-approaching coalition relative to the competition. A similar rule is used in Ecuador2, as well as some Argentine provinces and for Uruguayan presidential primaries.
The DCR or any of the existing “qualified plurality” rules would be better than the majority-runoff rule, which may still give Haiti a runoff it does not need, or the 40% rule, which will not give Costa Rica a runoff it arguably should have.
1. Don’t feel to bad for Manigat if he does not get to play in a runoff. In 1988, he narrowly averted a runoff with 50.2% and a runner up at 19.7%. So he’s been on both sides of this wide-first-round-lead thing. (Of course, about six months after his decisive win he was sent off into exile.)
2. In Ecuador, the leading candidate must have at least 40% and a ten-point lead; unlike in Argentina, 45% with a smaller lead is not good enough. There is a similar provision in the Nicaraguan constitution, where the president needs 40% or 35% with a lead of at least five percentage points.
Epilogue: I might also note that today happens to be the birthday of the man who won the US presidency with the smallest plurality in history. Lincon had only 39.9% of the popular vote in 1860. The runner-up, Stephen Douglas had 29.5%. Lincoln’s plurality would have just barely sufficed under the DCR, but obviosuly not under Haitian rules and would have been just barely insufficient under Costa Rican rules.