A Panamanian national holiday remembering the killing of 21 protesters by police and U.S. troops in 1964 is taking on new resonance this year as U.S.

Treaties ratified by the Senate in 1978 established permanent neutrality, but some Republicans regret that decision.

This time, the holiday was marked by patriotic anger stirred up by President-elect Donald Trump, who has called for the canal to reverse to American hands, potentially by military

For weeks, Donald Trump has been stating his intention to take control of the Panama Canal, a critical 51-mile long waterway that connects the Atlantic and Pacific oceans.

Few took the president-elect’s combative comments at face value, but they still sent a shudder through a country that the United States has invaded before.

Control of the Panama Canal, once a key U.S. presidential campaign issue for Ronald Reagan and an animating topic for people ranging from film legend John Wayne to an unpredictable Canadian-born U.S.

Built and managed by the US for several years, the Panama Canal was transferred back to the country in 1999. It is this decision that US President-elect Donald Trump is now bringing into question.

Panama Canal Administrator Ricaurte Vásquez addresses President-elect Donald Trump's suggestion that the U.S. should retake control of the Panama Canal during an interview with Associated Press in his office Friday,