For two years, the Organization of the Petroleum Exporting Countries has appeared powerless to stop a slide in prices that has punished the economies of oil-dependent members, including Saudi Arabia. Such a state of affairs calls into question whether the once-powerful cartel is still a relevant force in today’s market. The group reasserted itself in September in Algiers, saying its members agreed to cut production. Details are to be ironed out in Vienna on Nov. 30. But doubts remain as to the likelihood of a meaningful accord. To explore OPEC’s ability to act effectively, The Wall Street Journal consulted a panel of experts: Jason Bordoff, professor of professional practice in international and public affairs and founding director, Center on Global Energy Policy, at Columbia University; Helima Croft, head of commodity strategy, RBC Capital Markets; […]