Why did the United States enter the Persian Gulf War?

The United States entered the Persian Gulf War primarily to force the Iraqi military from Kuwait. In August 1990, Iraq, led by President Saddam Hussein, invaded Kuwait, an act that was met with widespread international condemnation. The invasion threatened not only Kuwait's sovereignty but also posed a significant risk to global oil supplies, as Kuwait is a major oil-producing nation.

The U.S. response was to form a coalition of nations, including allies from Europe, the Middle East, and other areas, to counter Iraq's aggression. The goal was to liberate Kuwait and restore its independence. This coalition launched Operation Desert Storm in January 1991, which successfully expelled Iraqi forces from Kuwait by the end of February 1991.

While the other options touch upon aspects of U.S. foreign policy and international relations, they do not encapsulate the immediate and direct reason for U.S. military action in the Gulf War as effectively as the aim to remove Iraqi forces from Kuwait.