This is why Frank Capra, contrary to popular opinion, is one of the most challenging of all filmmakers and in some ways the most disturbing. Most "serious films"—the "hard-hitting" "uncompromising" films—ask us only to accept, for example, that poverty is bad, relationships are hard, that politics is corrupt. In short, their "challenge" consists precisely in asking us to accept ideas that we already accept anyway, even if we struggle to know just what to do about them. In these comedies, Capra asks us to accept that the old-fashioned American ideals are still good, that David really can whip Goliath, that our prayers do not go unheard, that the meek shall inherit the earth. In other words, he asks us to accept things about which we have grave, grave doubts. And he is uncompromising in his asking: he doesn't ask us to accept these propositions as nice or inspirational or comforting or helpful—he asks us to accept them as true.
Rod Bennett, The Gospel According to Frank Capra