SAO PAULO (AP) — Microphone in hand and standing atop the sound truck, the raspy-voiced protest leader jabbed his finger into the air shouting for the ouster of Brazilian President Dilma Rousseff, igniting wild cheers from the crowd below him.

"What Lula and Dilma have done shouldn't just result in their being banned from politics. It should result in them being in jail!" Kim Kataguiri yelled, denouncing Rousseff and her predecessor, Luiz Inacio Lula da Silva.

The March 15 demonstration was the largest Sao Paulo had seen in more than three decades, since 1984 protests demanding democratic elections after a long dictatorship.

But more surprising than the crowd of more than 200,000, according to the Datafolha polling and statistics agency, was the fact it was being led by Kataguiri, a skinny, 19-year-old college dropout, and other young Brazilian activists inspired by libertarianism and conservative free-market ideals.