The United States has officially refused to extradite a Cuban man to Venezuela to face terrorism charges. The man — Luis Posada Carriles — is wanted to stand trial for the 1976 bombing of a commercial airliner that killed 73 people. Posada is a U.S.-trained Cuban exile who has been trying to violently overthrow Fidel Castro’s government for the past 40 years. He snuck into the United States two months ago and is seeking political asylum. The Cuban and Venezuelan government have accused the Bush administration of harboring a terrorist.