“WHEN a woman enters politics, it changes her. When many women do, it is politics that changes.” So said Florentina Gómez Miranda, a former Argentine congresswoman. Despite its macho reputation, or perhaps because of it, Latin America is unusually keen on quotas for female political candidates. In 1991 Argentina became the world’s first country to require parties to nominate women in a minimum fraction of races. Today, of the 18 Spanish- or Portuguese-speaking countries in the Americas, 17 have a version of this policy. Elsewhere, around a third do. Five of the world’s nine most female lower houses are Latin American. One of them is in Mexico, which on July 1st elected a near-even split of the sexes in both chambers.

Many Latin countries got rid of dictatorships in the 1980s, creating a group of young democracies unbound by precedent. Yet just 5% of elected legislators that decade were female. Feminists, many of whom had campaigned for democracy, began painting political parties as sexist relics for failing to run female candidates. Argentina responded by imposing quotas on parties, and fellow Latin American states followed suit.

Quotas did not always achieve the intended result. In Brazil, where just 11% of lower-house members are women despite a 30% quota, parties can run multiple candidates for the same seat. They nominate the required share of women, but give more support to men. In some countries the old guard resorted to tricks. In Bolivia, male candidates registered for elections in 1999 with female variants of their names, like “María” for “Mario”. When Mexico introduced a 30% quota in 2002, its parties ran women in unwinnable districts, and put them at the bottom of party lists. In 2009, after the rules were tightened, eight female lawmakers quit within a week of being sworn in. Men took their places.

Only on the third try did Mexican quotas work as planned. In 2014, a constitutional amendment raised the minimum to 50%, and required understudies to be the same sex as the people they would replace. The new rules were applied to both houses for the first time this month.

Critics of quotas contend that they deprive voters of a free choice of candidates, though under the proportional representation (PR) rules that govern many Latin elections they never had that in the first place. Other critics fret that women elected under quotas are likely to be less qualified, or puppets of male relatives. Jennifer Piscopo of Occidental College in Los Angeles says that most studies show the women are as accomplished as men. (In some places, that is a low bar.) Only one country in the Americas, Haiti, reserves seats for women. In the rest of Latin America, women must either win an election to hold office or, under PR, appear high enough on a party list.

Despite the quotas, women still hold a small share of the most important legislative jobs. And the region’s number of female presidents has fallen from four in 2014 to zero today. Unsurprisingly, quotas have increased the number of female lawmakers—especially since those lawmakers tend to vote to raise the quotas still further.

Whether quotas yield laws that improve women’s lives is harder to answer. In the 12 years to 2009, female lawmakers in Mexico were six times more likely than males were to introduce bills invoking women’s rights or children’s well-being. But a study of Argentina found that although the number of female-friendly bills rose as more women entered Congress, the share that became law fell. More female legislators do not necessarily boost women’s voices in civil society or the press, which help to get bills over the line.

Nonetheless, female lawmakers and academics insist that quotas have borne legislative fruit. Argentina’s recent reform to increase access to contraception needed a critical mass of women in Congress to pass, says Ms Piscopo. Similarly, Mexico is on the verge of approving a law aimed at curbing political violence against women. “If women don’t promote it,” says Cristina Díaz Salazar, a senator, “it doesn’t pass.”