When Colombian former President Gustavo Petro convened an emergency CELAC session in the first week of January, the assumption in most South American foreign ministries was that the region would answer the United States with one voice. Eight months later, the answer is still fragmented — and Venezuela's oil is flowing north at a rate not seen in two decades.

When Colombian former President Gustavo Petro convened an emergency CELAC session in the first week of January, the assumption in most South American foreign ministries was that…

An accord anchored on billions of dollars lacks the depth needed to transform a neglected national oil industry, an expert writes.