When Dilma Rousseff was elected president of Brazil in 2010, industry was thriving and her goal of stamping out poverty in the world’s seventh-largest economy appeared within reach. Many Brazilians hoped that Ms. Rousseff, a former political prisoner, would establish a legacy as a transformational head of state at home and abroad.

So far, those hopes appear to have been misplaced. Ms. Rousseff has been an underwhelming leader on domestic matters and, perhaps most disappointing, on the world stage. While the other three large emerging economies, China, Russia and India, are pursuing muscular foreign policies, under Ms. Rousseff’s watch, Brazil’s voice in the international arena barely registers above a whisper.

After being re-elected by a tiny margin last fall, Ms. Rousseff is now facing the most turbulent period of her political career. The economy is sputtering, and Brazilians are enraged by the widening corruption at Petrobras, the state-owned oil company, which has tainted top figures from the ruling Workers Party. With thousands of Brazilians taking to the streets to protest Ms. Rousseff’s leadership, and some calling for her impeachment, the president will very likely be tempted to hunker down and focus on weathering the political crisis.

While restoring the trust of constituents will undoubtedly be tough, Ms. Rousseff would be wise to spend more energy looking outward, to help strengthen the country’s economy.