Prosecutors in Florida have filed homicide conspiracy charges against Raúl Castro and asked for the arrest of the former Cuban leader. The case reaches back to 1996, when two light aircraft were shot down by Cuban military jets. The four people killed were members of a humanitarian group that flew over the Florida Straits searching for migrants at sea. Charges of this kind against a former head of state are rare, and an actual arrest is very hard to imagine. The filing still carries legal weight, because it can restrict travel and fixes the accusation into a formal record. Havana reacted quickly, branding the whole exercise a political maneuver. Relations between Florida officials and Cuba have been sour for decades, and the new charges guarantee they stay that way.