Most countries have land borders and voters. For them isolation was never feasible. Instead, they have adopted a confusing, illogical mess of rules. America bars travellers from Britain and the European Union, its closest allies and trade partners, and also two of the most vaccinated big places in the world, while admitting those from South-East Asia, where the Delta variant is rampant. Thailand bans entry from some countries and requires all other travellers to submit to a two-week quarantine. Yet of 21,038 cases identified on August 10th, only 19 were imported. Once a variant of the virus has started to spread in the local population, infections double every couple of weeks. Entry bans make very little difference to the total caseload.