Ok so the Panama Canal was given to Panama after being built and controlled by the USA. It was transferred by treaty to Panama, titled "The Treaty Concerning the Permanent Neutrality and Operation of the Panama Canal." This treaty was ratified by the Senate and thus is federal law. Under this treaty the U.S. retained the permanent right to defend the canal from any threat that might interfere with its continued neutral service to ships of all nations and that Panama would assume full control of canal operations and become primarily responsible for its defense. Trump's interest in the Panama Canal is not necessarily about acquiring the canal. The actual issue is that China now controls two of the five ports adjacent to the canal: Balboa on the Pacific and Cristobal on the Caribbean through Hutchinson Port Holdings Limited, a subsidiary of China controlled Hong Kong-based CK Hutchison Holdings Limited.

So again liberals always get upset about things Trump says. So this is a common pattern with Trump, threaten big consequences if a smaller problem is not fixed. So there is a problem, the Chinese control of these ports violating the permanent neutrality and Panamanian operation of the canal as the treaty states. This is the problem Trump wants fixed and if Panama does not fix it, he is threatening to take the Canal back under the treaty which we have reserved the rights to do. I wouldn't expect taking the canal back to happen but I do expect to see more Panamanian control of the canal ports and fair and neutral treatment of US shipping especially in the fee department.

Also keep in mind that the only reason Panama is an independent country at all is because of US backing. The US purchased the Canal zone from the French Compagnie Universelle du Canal Interoceanique which had tried to build the Canal first and had secured use and control of the Canal Zone from them "in perpetuity," then shortly thereafter backed the Panamanian independence declaration from Columbia. So Panama is just a puppet state of the United States. Always has been, always will be. Oh yeah! Panama! Pan-a-ma-a!