The following has been attributed to the German physicist Werner Heisenberg:
History legitimizes Germany to rule Europe and later the world. Only a nation that rules ruthlessly can maintain itself. Democracy cannot develop sufficient energy to rule Europe. There are, therefore, only two possibilities: Germany and Russia, and perhaps a Europe under German leadership is the lesser evil.
Quoted sources include:
A 1943 letter from Heisenberg to Dutch scientist Hendrik B. G. Casimir (Blood and Water, Dan Kurzman, 1997, p. 35, ISBN 0-8050-3206-1 (from here).
Third-hand report: "it was filed in 1945 by the Dutch-American astronomer Gerard Kuiper, a member of the Alsos mission, to whom it had been relate by Casimir. Casimir alleged that Heisenberg had said this to him during a private walk in Leiden, during which he had also learnt that Heisenberg knew at the time about the German concentration camps. It isn't clear that Casimir s report can be taken at face value." (from this book).
Is this quote correctly attributed/better documented? Or is there any other evidence Heisenberg was this sort of nationalist?