It's unclear how the issue of ownership of the Panama Canal became a talking point for President-elect Donald Trump this week, but the question has a long political history.

Trump again having designs on Greenland comes after the president-elect suggested over the weekend that the U.S. could retake control of the Panama Canal if something isn't done to ease rising shipping costs required for using the waterway linking the Atlantic and Pacific oceans.

President-elect Donald Trump ran on a platform of isolating the US from foreign conflicts like the Ukraine war, increasing tariffs on foreign trade partners, and rebuilding domestic manufacturing. But in recent days he has suggested a more outwardly aggressive approach for his foreign policy.