The programme resumes after a 25-year hiatus, teaching soldiers, sailors and Marines rainforest survival, medical evacuation and patrol skills in Panama.
Its return gains urgency as President Donald Trump signals possible strikes on Mexican cartel leaders and action against Cuban defences.
Those threats have rattled Latin America, especially after Trump's surprise capture of Venezuelan President Nicolás Maduro in January made such warnings appear more credible.
With US forces at its doorstep and allies falling, can Cuba's government survive Washington's final push?
How will China retaliate as the U.S. dismantles its strategic economic footholds across Latin America?
Is America's new 'Donroe Doctrine' a path to stability or a trigger for wider conflict with China?