The inability of U.S. presidents before Barack Obama to find a winning formula on climate change has been the Achilles’ heal of global climate negotiations. But President Obama has brought a new voice to U.S. climate diplomacy and U.S. leadership will be a major contributor to a successful outcome at the Paris COP. Bob Sussman examines the causes of failed leadership in previous administrations and how three important factors have converged to create a new negotiating dynamic that may enable the president to succeed where his predecessors came up short.