RESPLENDENT in high-heels and handbags from the world’s priciest designers, Elba Esther Gordillo (pictured), the leader of Mexico’s powerful teachers’ union, has never made any secret of her wealth. Mexicans have long wondered how she is able to maintain her lavish lifestyle on a public servant’s salary. On February 26th federal prosecutors announced what they think is the explanation: the alleged embezzlement of 2 billion pesos ($159m) of union funds. Ms Gordillo, who likes to be known as “la Maestra” (“the Teacher”), was arrested at an airport outside Mexico City.

Jesús Murillo Karam, the attorney general, said Ms Gordillo and two other union officials had spent the money on designer clothes, art, property and cosmetic surgery. Some of the funds were transferred to companies in Switzerland and Liechtenstein registered in Ms Gordillo’s mother’s name, before being used to buy houses in San Diego. This may not be the full extent of the swindle, prosecutors said. “La Maestra” has not yet commented though her union colleagues have come out in her defence, saying they “believe in” her.

Her arrest looks like a calculated show of strength by Enrique Peña Nieto, Mexico’s new president. It came the day after he signed into law an education reform designed to prise control of schools from the hands of the union. And it may just be intended to send a broader message to those who flaunt unaccountable power.

Ms Gordillo has led the 1.5m-member teachers’ union for 23 years, spanning five presidencies. In October she was elected unopposed for another six-year term. She has held a baleful influence over education in Mexico, taking advantage of rules which delegate to the union the hiring and promotion of teachers, as well as the payment of their salaries via opaque accounts. Having been a boss of Mr Peña Nieto’s Institutional Revolutionary Party (PRI), after the party lost power she opportunistically switched her (and the union’s) support in 2006 to Felipe Calderón, who won the presidency for the conservative National Action Party. She set up her own political outfit, which though small has sometimes tipped the balance at elections.

The government has promised that from now on teachers’ jobs will no longer be for sale, or inherited. Teachers who fail assessments will face the sack. The union has organised marches against the proposals. It is unclear whether the downfall of Ms Gordillo will defuse these protests.

The arrest of “la Maestra” mirrors that in 1989, six weeks into the presidency of Carlos Salinas, of Joaquín Hernández Galicia”, the head of the oil workers’ union (who had failed to back Mr Salinas’s dodgy election). That was both an exercise of presidential authority, and a prelude to liberal economic reforms. Some of Mr Peña’s close aides have ties to Mr Salinas.

Mr Hernández was promptly locked away. Convicting Ms Gordillo may prove harder. Mexico is now a democracy, unlike under Mr Salinas: judges are more independent; those who are not are biddable by actors besides the president. In recent years lack of evidence or procedural errors have made several big cases collapse.

Who might be next for a come-uppance? Reports have recently appeared in the Mexican press of a limited-edition Ferrari bought by Carlos Romero Deschamps, the current leader of the oil workers’ union, as a gift for his son. But as a newly elected PRI senator, Mr Romero—against whom there is no evidence of wrongdoing—is in a stronger position than Ms Gordillo. Whereas the government’s early announcements suggested that the writing was on the wall for “la Maestra” (her allies were passed over for senior jobs at the education ministry), it has indicated that the shake-up of the state-owned oil industry will not be as radical as some had hoped.

Even so, Ms Gordillo’s downfall may help Mr Peña counter criticism that he is too cosy with vested interests that flourished under the PRI’s long rule to 2000. (Andrés Manuel López Obrador, the left-wing runner-up in last year’s election, predicted that Mr Peña would appoint Ms Gordillo as his education secretary.) Like Mr Salinas’s strike against Mr Hernández, the arrest sends a message that the government is serious about some reforms, at least. That may be noted by the country’s telecoms and media barons, who face a law to introduce more competition in telephony, internet and television.

But first the case against Ms Gordillo must stick. If it falls apart, it may only embolden Mexico’s other de facto powers. Salinismo in democracy, which Mr Peña’s government in some ways resembles, faces its first test.