Among the world's hotly contested, obsessively controlled, and often dangerous borders, none is deadlier than the Mediterranean Sea. Since 2000, at least 25,000 people have lost their lives attempting to reach Italy and the rest of Europe, most by drowning in the Mediterranean. Every day, unauthorized migrants and refugees bound for Europe put their lives in the hands of maritime smugglers, while fishermen, diplomats, priests, bureaucrats, armed...