A former economic advisor to the White House and Treasury Department, Dr. Nouriel Roubini explains why the world's economy got into its current financial mess and how to fix it. In 2005, Roubini warned that the U.S. housing bubble was set to explode and bring global financial systems to a screeching halt. With his concerns now reality, he contends that no amount of stimulus spending can end the crisis until the massive imbalances at its heart are resolved.