Back in 2015, Brazil was introduced to a group of teen libertarians who used social media to defend public spending policies as tight as their jeans and demand the impeachment of then-President Dilma Rousseff. Through organizations such as Movimento Brasil Livre (the Free Brazil Movement, or MBL) and Vem Pra Rua (Take to the Streets), these youngsters were a pivotal part of the political crisis that engulfed Ms. Rousseff’s center-left administration. They helped orchestrate massive protests that culminated in her ousting by Congress one year later.
In subsequent years, these organizations seemed to adapt to the political landscape they once...
