ON MARCH 4, the 4,309-ton French freighter La Coubre, carting seventy-six tons of Belgian grenades and ammunition to the army of Fidel Castro, exploded in Havana harbor, killing more than seventy-five seamen, dock workers and firefighters. The series of deadly blasts triggered a series of sensational questions that hit headlines in both the United States and Cuba. Had an American agent or anti-Castro Cuban slipped aboard and left a time bomb in the hold? Had a careless dock worker dropped a match into the munitions? Had a cargo net snapped, unleashing crates of grenades against the deck? Had a plane sneaked low across the harbor and tossed bombs into the freighter? Other questions, tinged with less excitement, were also evoked. But, too theoretical, old and uncomfortable, they made few headlines. They are questions which have arisen time after time, applied to incident after incident, in the last decade. Their most cogent expression came from Colombian liberal Eduardo Santos in 1955. “Against whom are we Latin Americans arming ourselves?” he cried out before a Columbia University forum...