Kallen (who is news to me) coined the phrase cultural pluralism.
Multiculturalism in contemporary Western societies
Monument to Multiculturalism by Francesco Pirelli in Toronto, Canada. Four identical sculptures are located in Buffalo City, South Africa; Changchun, China; Sarajevo, Bosnia and Sydney, Australia.Multiculturalism has been official policy in several Western nations since the 1970s, for reasons that varied from country to country,[18][19][20] including the fact that many of the great cities of the Western world are increasingly made of a mosaic of cultures.[21] However, in recent months, several heads-of-state have expressed doubts about the success of these policies: The United Kingdom's Prime Minister David Cameron, German Chancellor Angela Merkel, Australia's ex-prime minister John Howard, Spanish ex-premier Jose Maria Aznar and French President Nicolas Sarkozy have voiced concerns about the effectiveness of their multicultural policies for integrating immigrants.[22]
In the Western English-speaking countries, multiculturalism as an official national policy started in Canada in 1971, followed by Australia, where it has since been displaced by assimilation, in 1973.[23] It was quickly adopted as official policy by most member-states of the European Union. Recently, right-of-center governments in several European states—notably the Netherlands and Denmark— have reversed the national policy and returned to an official monoculturalism.[23] A similar reversal is the subject of debate in the United Kingdom, among others, due to evidence of incipient segregation and anxieties over "home-grown" terrorism.
http://en.wikipedia.org/wiki/Multiculturalism