Brazil’s longest serving Supreme Court Justice Celso de Mello retires from the court this afternoon, 31 years after first occupying his seat. His vacancy has offered far-right President Jair Bolsonaro his very first shot at appointing a justice to the Supreme Court — a process that is often fraught with realpolitik and cynical self-preservation. However, Mr. Bolsonaro’s pick — 48-year-old federal judge Kassio Nunes Marques — came as something of a shock to political pundits in Brasília.
Despite having promised an ultra-conservative and “extremely Evangelical” appointment to the Supreme Court, Jair Bolsonaro selected a justice with long-term...