In his 2008 book Et Delt Folk ("A Nation Divided"), The Danish historian and writer Morten Uhrskov Jensen carefully went through publicly available sources. He demonstrated that the opening up of his country for mass immigration was arranged by just part of the population, sometimes in the face of considerable popular opposition.
Roughly speaking, those representing the political and media establishment and the upper classes were in favor of open borders, whereas those from the lower classes were often opposed. This divide is viewed by those from the upper segments of society as caused mainly by racism, prejudice, ignorance and xenophobia.
Since the educated classes enjoyed a virtual hegemony over public debate, they were able to define all opposition as hate and intolerance, exemplified by people such as Pia Kjærsgaard of the Danish People's Party. The well-to-do themselves rarely lived in areas with many immigrants and could afford to move, at least for a while, if that was needed. They focused on the abstract and allegedly humanitarian aspects of mass migration.