虽然美国领导人，包括奥巴马在内，一直抱怨有人免费搭车，但美国一直在提供安全、稳定的国际储备货币、相对开放的市场和地球公共资源管理等全球关键公共服务方面发挥着领导作用。
While American leaders, including Obama, have complained about free riders, the US has long taken the lead in providing key global public goods: security, a stable international reserve currency, relatively open markets, and stewardship of the Earth’s commons.