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

Hundreds of Panamanians marched on Thursday to mark the anniversary of a deadly uprising against U.S. control of the Panama Canal in 1964, with some protesters burning an effigy of President-elect Donald Trump who has threatened to retake the vital global waterway.

If commercial fees are typically low and America’s navy already has cheap and preferential access, why is Mr Trump threatening to take the canal? The simplest answer may be that the president-elect is expressing geopolitical machismo,