In just two months, Brazilian President Jair Bolsonaro has managed to do something that has taken past presidents years: losing 15 percentage points in popular support. The rate of voters which consider his administration as doing a “good” or “great” job has gone from 49 percent in January, to 39 percent the following month—to just 34 percent now. Meanwhile, the administration is rated “O.K.” by 34 percent, with one-quarter of voters placing Mr. Bolsonaro’s performance as either “bad” or “terrible.”
While...