The ongoing football World Cup provides a stark lesson, where nations thrive not by excluding but by embracing as many nationalities as possible to make their citizenry. To demand some other atavistic proof of kinship would be to deny the very cosmopolitanism that makes modern societies thrive. The US, more than other countries, should know this. Its innovation economy has been built much on 'imported' talent. Universities, companies and research labs flourish when they attract minds from across the globe.