Obama's foreign policy legacy still to be determined

WASHINGTON — President Barack Obama's foreign policy legacy may be defined as much by what he didn't do as by what he did. Over eight years, Obama ushered in a new era of diplomacy, re-establishing the United States as the driving force behind fighting climate change and reducing the threat of nuclear weapons. He restored unity between the U.S. and its allies after the divisive tenure of President George W. Bush and avoided adding another large-scale U.S. military commitment overseas. But Obama also ran headlong into his limitations as the world's chief diplomat. His cautious and pragmatic approach to world affairs ultimately couldn't deliver on the founding promise of his presidency: ending...