From Vietnam to Afghanistan, Iraq to Syria... the US sent its troops marching on foreign soil time and again, yet almost every time it failed to change these occupied countries for the better. They’re instead left in turmoil and despair. History always repeats itself, but why doesn’t the US learn from it? What is driving this US behavior? Jeffrey Sachs is Professor and Director of the Center for Sustainable Development at Columbia University. He took a sharp, unflinching look at US foreign policy in a conversation with CGTN host Tian Wei.