The incumbent president of Mexico, Andrés Manuel López Obrador — usually known by his initials, AMLO — is so popular that he almost certainly would have won another term if his name had been on the ballot last Sunday.
But Mexico’s Constitution has a strict one-term limit for presidents. So instead, Claudia Sheinbaum, a climate scientist and the former mayor of Mexico City whom López Obrador anointed as his chosen successor, ran and won a landslide victory.
One-term presidential limits are relatively rare. Many countries, like the U.S. and France, allow two terms. In parliamentary systems like Britain, Spain and Canada, there are no term limits: Prime ministers are technically chosen by their party, not the voters (though the party officials who choose them are often elected by the public), and can stay in office as long as their party heads, the government and their parliamentary colleagues support them.
The downsides of a one-term limit are fairly obvious: an elected president might be just getting into his or her stride on an ambitious long-term policy goal or structural reform. Leaving after one term might mean that important work is left unfinished, or easily erased by a successor.
Some might argue that the whole concept of term limits is undemocratic. Their purpose, after all, is to prevent the public from electing their first-choice candidate if that person has already held office for the maximum time permitted.
So why shouldn’t voters get to choose for themselves?
The answer, experts say, lies in the delicate balance required to protect democracy from itself.
Term limits can guard against the forces that would otherwise make presidential systems vulnerable to democratic backsliding or autocracy. And there isn’t a one-size-fits-all solution: Some countries may benefit more from shorter term limits if, for example, they have high levels of corruption or a recent history of dictatorship.
Yes, you can have too much democracy
Over many years of talking to experts who study democratic backsliding, I’ve often heard some seemingly strange advice: If you want to protect democracy, it’s best not to have too much of it.
I know, it sounds paradoxical. But democratic systems need more than voter choice to be stable. They also need checks and balances to prevent one person or party from accruing too much power, and institutions that can make the system function.
Take referendums. They’re often portrayed as the purest form of democracy, but political scientists have found they can subvert rather than uphold it. Because voters tend to be working from relatively little expertise or information, referendums often put power in the hands of elites who can shape news media narratives. And direct votes tend to be volatile, turning on unrelated partisan sentiments.
The consequences of the Brexit referendum, around which misinformation was rife, bear out that criticism. Fifty-six percent of Britons now say that voting to leave the E.U. was a mistake, and only 9 percent consider Brexit a success, according to a recent YouGov poll.
So although unfettered vote choice, whether for a policy or a president, may seem like the purest democratic option, it’s not always the best. Voters might not realize that re-electing presidents for multiple terms could allow them to entrench their power, ultimately undermining democracy in the longer term. Term limits build automatic protections into the system.
A buffer against wannabe dictators
During the so-called “third wave” of democratization in the late 20th century, countries that were exiting authoritarianism — including many in Latin America — wrote new constitutions to enshrine democratic norms, often including term limits.
They represented “an important check on executive power to make sure that those authoritarian regimes could not re-emerge,” said Kristin McKie, a political scientist at St. Lawrence University in New York.
Mexico’s presidential term limit dates back more than a century to the revolution that ended the “Porfiriato,” a dictatorial regime led by Porfirio Díaz, who ruled Mexico for nearly 30 years.
“Díaz’s prolonged hold on power was one of the causes of the Mexican Revolution,” said Mariano Sánchez-Talanquer, a political scientist at El Colegio de México in Mexico City. “‘Effective suffrage, no re-election’ was one of the revolution’s rallying cries.”
The revolution of 1910 didn’t bring democracy, but instead ushered in one of the longest single-party authoritarian regimes in history. Governments in that era still respected the letter of the law on re-election, with presidents holding office for six years and then handing over power to a chosen successor who would “win” a noncompetitive election.
That tradition meant that when Mexico eventually did make the transition to democracy at the end of the 20th century, the ban on presidential re-election was a robust norm. To try to evade or change it would have been taboo, even for a popular president like AMLO.
A number of experts told me that Mexico’s one-term limit was a good thing, especially because its presidential terms, at six years, are already quite long.
“The strength of the no re-election rule in Mexico helps protect the country against democratic breakdown,” Sánchez-Talanquer said.
Steven Levitsky, a Harvard political scientist and the co-author of “How Democracies Die,” agreed. “For a new democracy, or a fragile democracy, rotation in power is critical,” he said, adding: “Another six-year term by AMLO, I think, would have been very dangerous.”
In a number of other Latin American countries, including Venezuela, dismantling or evading term limits has been an effective tactic for populist leaders who reach power democratically, only to undermine democracy once in office.
And if a term limit is ignored once, it will probably be ignored again. The longer presidents are in office, the more opportunities they have to pack courts with allies to rubber-stamp their agenda.
Those effects are even more significant in countries with high levels of corruption, and where politicians trade material gains, such as government jobs or contracts, for political support. Longer terms mean more time to build patronage networks to shore up personal power.
Not all politicians need term limits
Interestingly, term limits don’t seem to be as important for legislators. For them, experience is very valuable, McKie said, and term limits can make legislative bodies less effective at policymaking. Because legislative power needs to be exercised collaboratively, there’s less risk of a single member of a congress or parliament winning enough authority to dismantle democracy.
Even presidential term limits are hardly a silver bullet for protecting democracy, however. In Mexico, “there are clouds on the horizon,” Sánchez-Talanquer said. Sheinbaum has promised to support AMLO’s proposed package of constitutional reforms, which would concentrate more power in the presidency by weakening opposition parties and making judges and election authorities into elected officials subject to a popular vote. Elected judges and officials are often a less effective check on the other branches of government, particularly when the politicians they’re supposed to be checking are from their own party, or are very popular with the public.
And although AMLO will formally leave office at the end of his term, it remains to be seen how much influence he could have on Sheinbaum.