Reston's book was meant as part of a wake-up call to those who'd buried their heads in the sand--much as England had slept (to borrow the title of young JFK's monograph). It fits in with the type of realization that filmmakers such as Frank Capra had when they viewed the hyper-aggressive militarization of the Axis powers. As Mark Harris notes in FIVE CAME BACK, it took a lot of work to shake Americans out of their lethargy--particularly since they were just beginning to feel that they'd survived the longest economic crisis in the nation's history.
Reston uses a 40s version of "shock and awe" to bring this into play and help motivate ordinary Americans. It was especially needed in the early days of WWII, when the USA was struggling to get a credible war effort underway. It is a dark moment, to be sure--but there is ample room for disagreement, with or without footnotes, as to whether it represents the lowest ebbing of the American spirit. If anything, it is a cry of dismay for the fact that America had kept its head in the sand for so long regarding the worldwide totalitarian menace.
And it is reflected in the gloom, grief, dread that begins to surface significantly in films during 1942--parallel to but mostly independent from a similar foreshadowing, an analogous mingling of treachery, oppression, betrayal, and double-dealing that we see in the exotic spy noirs in France from 1936-39. These, alongside the poetic realist films, which often use exotic locations, all score high in terms of a resignation to one's fate, a sense that forces outside one's control (the rise of totalitarianism) will soon overpower and obliterate life as it had been known.
This all happens in tandem with or ahead of the Anglo-American films; the anticipation of dread, the lingering sense of impending disaster, is something that originates in mid-to-late 30's French cinema. What we have in France is a different form of denial as manifested by the media, which didn't want to heed the warnings that Duvivier, Renoir and Carné implanted in their films.
For America, which had been preoccupied with its own ongoing economic sluggishness even in the midst of the New Deal, isolationism was an easy way to sweep aside the troubling events elsewhere. As Nazi aggression accelerated in 1937-38, Hollywood finally began to shake off those shackles and began to address the situation--but even then, isolationism (the origination point of that dubious slogan "America First") remained stubbornly implanted in the minds of most Americans. Once the war was finally thrust upon it, the USA began with a kind of whimper, and this is reflected in the sense of being enveloped by forces beyond one's control that permeate the early Lewton films.