The problem with “Perfidy” is that Hecht gives way too much power to Kastner. He alleges that Kastner single handedly had the koach to stop the Churban in Hungary but didn’t in order to get the Kastner Exchange (and Kindertransport I think?) off the ground.
Ironically, Hashem used Kastner as the shliach to save the Satmar Rebbe Reb Yoel ZT”L from the fires of Europe.