Marco Rubio on Venezuela:

Venezuela’s economy under Chavismo really had become something controlled by a network of corruption — by people who were stealing, including the individuals and countries that were stealing Venezuela’s wealth.

For example, Cuba was being given the value of several billion dollars in barrels of oil.

China paid very little for oil; they were getting it at a discount.

As for Russia, they were simply taking the oil as debt settlement. Many of Maduro’s friends and others also benefited.