Why does Isis slay hostages? To cover up the fact that it’s losing

At this point in the war between the jihadist group known as the Islamic State and a US-led international coalition, many observers are wondering how Isis keeps winning. Isis is up against western air power and powerful regional opponents, and yet has apparently seized a territory larger than the United Kingdom, and is expanding into Egypt, Libya, Algeria, Yemen, and elsewhere. It seems incredible.

But the truth is that it’s difficult to say Isis is winning by any objective measure. In Iraq, the group has been put on the defensive in the provinces of Nineveh, Salahaddin, and Diyala, and may soon face a major offensive on its stronghold of Mosul. It’s true, unfortunately, that Isis is on the offensive in Anbar province, and could potentially capture new territory there. In eastern Syria, too, Isis is well-established, having brutally suppressed a tribal uprising in Dayr al-Zawr, and it faces no significant resistance in its holdings in Raqqa and Hasaka.