What may be the largest corruption case in modern history runs deep in Latin America’s largest country. In U.S. history, entire cities and states have been branded corrupt: Think Richard J. Daley’s Chicago or Huey Long’s Louisiana. But amid even the worst federal scandals, Watergate included, the country has never been nationally profiled as crooked—a venal society from coast to coast, from dog catcher to commander-in-chief.   Brazil feels that way right now, largely the result of a bribery scandal…