There are moments when the edifice of propaganda collapses, when the images of emaciated children, pulverised neighbourhoods, and mass graves pierce the armour of denial. For Tucker Carlson and Piers Morgan, two men once counted among Israel’s most ardent defenders, Gaza became that moment. Their transformations—Carlson from a “rabid Zionist” to a relentless critic of Israel, Morgan from a staunch defender of its military campaign to a voice of outrage—are not anomalies. They are the inevitable consequence of witnessing a genocide in real time. Carlson’s metamorphosis was as startling as it was consequential. For years, he echoed the talking points...