The racist and antisemitic “great replacement” theory is encroaching out of the far-right and more visibly into mainstream US politics in the wake of its platforming by major figures like Elon Musk and Tucker Carlson, in a move experts believe shows the growing extremeness of rightwing politics in the US. High profile users of Twitter/X including rightwing personality Carlson and the platform’s proprietor Musk, are helping to mainstream extremist narratives that are increasingly prevalent on the site, experts and advocates say. Despite Musk’s aggressive responses to organizations that criticize X for promoting extremism, white nationalists and other extremists last week...