For journalists covering the world’s conflict zones, the occupational hazards include kidnapping, serious injury and even death. The fact that they assume such risks does not make it any less tragic or, potentially, threatening to press freedom when the risks materialize. Hence the May 11 shooting death of Shireen Abu Akleh, Al Jazeera’s star reporter, while covering Israeli-Palestinian fighting in the occupied West Bank is a reason to mourn — and to determine how and why it happened. The fact that Ms. Abu Akleh is a citizen of the United States, Israel’s key economic and military backer, gives the case special urgency.