Despite chill, cooperation between US and Russia

WASHINGTON - Since the Cold War ended two decades ago, Washington has considered Moscow mostly as an unreliable ally - and, at times, a stubborn adversary, in efforts to boost the global economy, curb weapons proliferation and calm other nations in tumult. At the same time, Russia's role as a key participant in international efforts to solve global crises gives it the ability to hurt the U.S. if it decides to be uncooperative or openly obstructive.