In the presidential elections in the United States, a certainty persists throughout the years: the one who wins is always a Republican or Democratic candidate.
This will be the case in the elections on November 3, and this has been the case for more than 160 years, despite the fact that other groups or independent candidates have competed against them to occupy the White House.
This ingrained bipartisanship can find an explanation in an old “law” of political science, the “ley Duverger”, by Maurice Duverger, the French sociologist who spread the bases for this theory.
What does it say and to what extent is it fulfilled?
Relative majority and single turn
Duverger published the book “Political Parties” in 1951, in which he says that a country’s voting system is a determining factor in whether it is bipartisan or multiparty.
In his text, Duverger says that the “majority and one-round vote tends towards party dualism”.
In other words, bipartisanship will be the norm in cases where to win the electoral process it is enough to obtain the largest number of votes, which is known as a simple or relative majority vote.
This system differs from those that provide for a second round among the most voted candidates if none exceeds a qualified majority threshold (for example, 50% plus one or, as in Bolivia, 40% with ten points of difference).
“The absence of a second round (…) especially in the presidential election, constitutes one of the historical reasons for the advent of bipartisanship and its maintenance,” says Duverger in his book.
Duverger points out that in the United States “traditional bipartisanship also coincides with majority scrutiny of a round.”
The presidential election in the US is indirect: the vote of the citizens serves to form the Electoral College, which is in charge of electing the president.
This is why we must understand the difference between popular vote, which is directly cast by citizens, and vote in the Electoral College in the United States.
Each US state elects a certain number of the 538 members that make up the Electoral College. To win the presidency, 270 of these electoral votes must be gathered.
In 48 states and in Washington DC, the candidate who obtains a simple majority of the popular votes gets all the representatives in the Electoral College. Only Maine and Nebraska are an exception in that they also award electoral votes to the winners in each district.
Thus, the US can be seen as a simple or relative majority system (one of the conditions Duverger talks about): uonly candidate wins everythings the electoral votes ofl status and nothing is distributed between second or third places.
“There is no benefit in being second, voters are not divided,” says Brian Gaines, professor of Political Science at the University of Illinois, to BBC Mundo.
“The two-party system has been elevated to the presidential elections thanks to the plurality component of the polling stations,” adds Gaines.
For example, in 1992, independent candidate Ross Perot participated in the presidential elections against Democrat Bill Clinton and Republican George HW Bush, and won 19% of the popular vote.
Perot was not enough to win any electoral vote.
In addition to this dynamic of the schools, there is no second round of the presidential elections in the United States.
If no one reached 270 electoral votes – something that has happened once in the United States – Congress would resolve the election.
This one-round, majority voting system has psychological effects on voters, Duverger notes in his book.
If a third party emerges, “voters often understand that their votes will be lost if they continue to give them to the third party: hence their natural tendency to make them fall back on the least bad of their adversaries, in order to avoid the success of the worst”, says the author.
“I think this law (of Duverger) reflects quite well what we see in the two-party system,” says David Paleologos, director of the Center for Political Research at the University of Suffolk, USA, to BBC Mundo.
According to this theory, “with a proportional (voting) system it would be enough to win political support for 5%, 10%, 20% of the vote, but that does not happen in this country,” he adds.
The system “forces people to think in terms of two parties and prevents third-party candidates from receiving support because they do not get any significant percentage,” adds Paleologos.
So small parties lose incentives to participate in elections.
“Although there are always people who vote for a third party or write someone else’s name. It is not that there are no other options,” says Paleologos. “There is not a single state that has only Biden or Trump, that’s what the pollsters say, but it’s wrong.”
But in the end, according to the Duverger law, “voter behavior tends to conform to the electoral system,” says the expert.
Bipartisanship also prevails in the US Congress, where there are only two independent senators (Bernie Sanders and Angus King) out of a total of 100, and a representative of the Libertarian Party, Justin Amash (although he had originally been elected as a Republican) , out of a total of 435.
But there are countries in which more than two parties have parliamentary representation, such as India and Canada, despite the fact that they elect the members of the lower houses of their Congresses and their rulers through majority votes in a single round.
These exceptions have led some to view Duverger’s “law” rather as a “hypothesis,” says Kenneth Benoit, professor of social sciences at the London School of Economics (LSE), in a 2006 article.
But Duverger himself clarifies in his book that the electoral system only “pushes” bipartisanship and that “it does not necessarily and absolutely lead to it despite all the obstacles.”
There may be many other trends “that dampen, slow down or stop” the bipartisan trend.
And in the US, rather, there are other factors that also contribute to bipartisanship.
One of them is the presidential system, says Patrick Dunleavy, a professor of political science at the LSE in a 2012 article titled “The Duverger Act is a dead parrot. Outside the US, first-round voting does not count. no tendency to produce bipartisanships “, in which he argues that this theory has become obsolete outside the US.
One more reason is that Americans vote in many more elections than other democracies, says Brian Gaines to BBC Mundo, such as elections for the House of Representatives, the Senate, state houses of representatives, state Senates, county offices, etc. ., so bipartisanship simplifies things.
All of these factors indicate that Republicans and Democrats will most likely continue to alternate the US presidency for several years.
Another factor contributing to bipartisanship in the US is the fact that each state has its own rules for registering as a candidate in presidential elections.
“What supports bipartisanship in the US is a wide range of laws that privilege Democrats and Republicans, and make it difficult for other parties to get on the ballot,” says Shaun Bowler, professor of Political Science at the United States. University of California at Riverside and editor of the book “Duverger Law of plurality voting”, to BBC Mundo.
“Look at the obstacles Kanye West must face to get on the schedule.”
Until the closing of this note, the American rapper had only managed to appear on the cards of 11 states.
“You have to meet the requirements of all 50 states, you need money, field operations. Ross Perot was a billionaire, so he could be on the cards of every state. But most would prefer to run within the structure of the Democratic or Republican Party.” , Paleologos tells BBC Mundo.
Not in vain Bernie Sanders, an independent senator from Vermont, sought the nomination as the candidate of the Democratic Party and President Donald Trump came to the White House as the Republican Party.
Para Bowler, Another of the great incentives of bipartisanship “is money.”
“Donors really do not want to give to minor parties with little chance of success,” he tells BBC Mundo.
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