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.

In recent weeks, when he was President-elect Donald Trump publicly said that Panama should return the Panama Canal to the United States, and he would not rule out using military force to reclaim it. At his presidential Inauguration on Monday Trump doubled down on saying that his new administration was going to take back the canal.

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.