While I have not read the book, I have read a few excerpts and am somewhat in agreement with D'Souza's some of D'Souza's conclusions. Namely that the decadence of the left has partially invited the wrath of our adversaries.
"In intention, at any rate, the English intelligentsia are Europeanized. They take their cookery from Paris and their opinions from Moscow. In the general patriotism of the country they form a sort of island of dissident thought. England is perhaps the only great country whose intellectuals are ashamed of their own nationality. In left-wing circles it is always felt that there is something slightly disgraceful in being an Englishman and that it is a duty to snigger at every English institution, from horse racing to suet puddings. It is a strange fact, but it is unquestionably true that almost any English intellectual would feel more ashamed of standing to attention during 'God save the King' than of stealing from a poor box. All through the critical years many left-wingers were chipping away at English morale, trying to spread an outlook that was sometimes squashily pacifist, sometimes violently pro-Russian, but always anti-British. It is questionable how much effect this had, but it certainly had some. If the English people suffered for several years a real weakening of morale, so that the Fascist nations judged that they were 'decadent' and that it was safe to plunge into war, the intellectual sabotage from the Left was partly responsible."