Answer:
In December 1989, the United States invaded the Panama Canal Zone to protect the Americans there.
Step-by-step explanation:
The US invasion of Panama in 1989 was a military operation of the United States Army carried out between December 20, 1989 and January 31, 1990, with the purpose of capturing General Manuel Antonio Noriega, de facto governor of Panama, who was required by the US justice for the crime of drug trafficking, as well as neutralizing the Panamanian Defense Forces and protecting the integrity of the American residents in the Canal Zone. The operation was called Operation Just Cause by the US military command, and resulted in approximately 3,000 deaths.