During Monday’s inauguration, Donald Trump repeated his threat to retake the Panama Canal. The United States controlled the waterway since the early 20th century, but in 1977 President Jimmy Carter signed a landmark treaty to give Panama control of the canal.

President Donald Trump has called for the US to retake control of the Panama Canal unless the cost of passage for naval and merchant ships is slashed. Trump’s refusal to rule out the use of force is a throwback to the 19th century era of gunboat diplomacy.

The answer is simple: there is no greater or more idealistic symbol of U.S. power in the world than the Panama Canal. As Trump seeks a way to enhance the country's power in the world, leaning on imagery regarding the Panama Canal provides just the right message.