With only days before the U.S. was due to default on its debt on June 5, months of squabbling among lawmakers has undermined people's confidence in the country. Washington also had much bigger problems to face, from political divide, high inflation to financial instability. CGTN's Guan Xin find out with Jeffrey Sachs, director of the Center for Sustainable Development at Columbia University and Li Daokui, director of the Academic Center for Chinese Economic Practice and Thinking at Tsinghua University, why the U.S. debt issue matters to the world.