In reaching November’s landmark agreement to reduce oil production, OPEC members labored for months to overcome their mutual suspicions and frequent mistrust. But reaching the deal could turn out to be the easy part—enforcing it could be another matter. The Organization for the Petroleum Exporting Countries has a history of failing to enforce its own production limits, according to numerous energy analysts and former OPEC officials. The cartel’s agreements usually spell out exactly how many barrels a day each member must cut. But ensuring that everyone abides by these quotas has been supported only by a fragile honor system, with OPEC having no official mechanism for punishing members that stray from their pledges. In 17 production cuts since 1982, OPEC members have reduced output by an average of just 60% of their commitments, according to Goldman Sachs. OPEC exceeded its quota by an average of 883,000 barrels a day […]