Socialist Unity on Venezuela’s threat to stop selling oil to the US if attacked by Columbia
If actually carried out, such a threat would be a big blow for the Venezuelan economy. More than 90 percent of its export earnings are from oil. The United States is the top buyer of oil from Venezuela, which is one of the U.S. main oil suppliers.
Fungibility is the property of a good or a commodity whose individual units are capable of mutual substitution. Examples of highly fungible commodities are crude oil, wheat, orange juice, precious metals, and currencies.
So, if Venezuela blocks direct oil sales to the US, someone else will buy their oil and perhaps sell it to the US. Or the US simply buys oil elsewhere.