Oil is responsible for the U.S. dependency on imports in the 21st century.

In the 21st century, oil has been the primary natural resource contributing to the U.S. dependency on imports. Despite advancements in domestic oil production, particularly through shale oil, the U.S. continues to rely on imported crude oil due to its high demand for refined petroleum products such as gasoline, diesel, and jet fuel. The global oil market and varying production levels in domestic fields mean that the U.S. must import oil from countries like Canada, Saudi Arabia, and others. This dependency remains a key factor in U.S. foreign policy and energy strategy, as maintaining energy security is crucial.