Alberto Youssef, a convicted money launderer and former bon vivant, sat in a Brazilian jail cell in March of last year, getting ready to tell his lawyers a story. It was about an elaborate bribery scheme involving Petrobras , the government-controlled oil giant. He opened with a dire prediction. “Guys,” Mr. Youssef said, “if I speak, the republic is going to fall.” To those lawyers, Tracy Reinaldet and Adriano Bretas, who recently recounted the conversation, this sounded a tad melodramatic. But then Mr. Youssef took a piece of paper and started writing the names of participants in what would soon become known […]