The primary thesis of the book is that Europe is far more dangerous than most Americans realize. Europe has a long and bloody history, and the relative peace of the postwar period doesn't represent a fundamental change in the European soul, but rather a lack of the practical possibility of waging war: After World War II, Europe was pressed between two superpowers against which no European country or coalition of European countries would be capable of waging war. Moreover, these two superpowers prevented any European country from attacking any other European country. With the end of the Cold War, the traditional danger posed by the European continent may once again come to the fore. Berlinski argues that the danger is far greater than most Americans (or anyone outside of Europe) realize. Factors leading to the "menace" in Europe include the lack of ability to integrate Muslim immigrants, which breeds Islamic radicalism, and a spiritual emptiness that leads to cultish hatred, in particular, Antisemitism and anti-Americanism.
One of the consequences of Berliniski's analysis is that the dream of a united Europe can never be fulfilled, for despite the anti-Americanism that she argues is a powerful glue holding European nations together, the enmity between these nations is ultimately too great to be overcome, and the cultural and historical differences between countries such as France and Germany can never be bridged.