Not long ago, Brazil stood as the leading example of how a developing nation could rise toward global prominence on the force of a China-driven commodity boom. As its economy surged, Brazil stormed the world stage—hosting a World Cup, demanding more say at the United Nations and blocking a U.S. free-trade plan for the Americas. Now Brazil is looking like a symbol of something else: resource-rich nations’ habit of ending their booms with spectacular busts. Brazil’s stock market is down 22% in the past year. Its currency has lost a third of its value against the dollar. And on Friday, Brazil is expected to report that in the second quarter, its economy shrank at a pace of about 1.7%. Economists are voicing fears of prolonged stagnation. China has caused turmoil in many places, but none more so than in this prime supplier of commodities to a country whose […]