MIAMI -- Deep in south Miami-Dade County, a group of people dress up in camouflage, pack high-powered weapons and train for a possible armed invasion of Cuba. They are members of Comandos F-4, a Cuban exile organization that thinks armed action is the only way to bring change to Cuba. It is one of the last paramilitary groups still training in the United States since the heyday of such organizations in the 1960s and 1970s, when bombings and armed incursions into Cuba were common occurrences. Since then, a number of the former militants have died and others have laid down...