The hypothesis, which seems to me the most fertile, is that news and truth are not the same thing, and must be clearly distinguished. The function of news is to signalize an event, the function of truth is to bring to light the hidden facts, to set them into relation with each other, and make a picture of reality on which men can act. Only at those points, where social conditions take recognizable and measurable shape, do the body of truth and the body of news coincide. That is a comparatively small part of the whole field of human interest. In this sector, and only in this sector, the tests of the news are sufficiently exact to make the charges of perversion or suppression more than a partisan judgment. There is no defense, no extenuation, no excuse whatever, for stating six times that Lenin is dead, when the only information the paper possesses is a report that he is dead from a source repeatedly shown to be unreliable. The news, in that instance, is not "Lenin Dead" but "Helsingfors Says Lenin is Dead." And a newspaper can be asked to take the responsibility of not making Lenin more dead than the source of the news is reliable; if there is one subject on which editors are most responsible it is in their judgment of the reliability of the source. But when it comes to dealing, for example, with stories of what the Russian people want, no such test exists.
The absence of these exact tests accounts, I think, for the character of the profession, as no other explanation does. There is a very small body of exact knowledge, which it requires no outstanding ability or training to deal with. The rest is in the journalist's own discretion.
Now, Lippmann states that 'there is a very small body of exact knowledge', but there is a much larger body than he would like to admit, particularly with respect to his own progressive movement. When guys like Wilson, Croly, and many, many others were out there disparaging freedom and the American way of life, where was Lippmann and other journalists and "muckrakers" to defend the people against it? They didn't, they were in on it! At best, you could highlight his opposition to the propaganda coming out of the CPI, but a very large body of those in the CPI were all journalists. His opposition to CPI was quite frankly not enough, considering how big the body of progressive thought was back then(and still is), and how dark it is. And if you look at what Media Matters/NBC are up to, they are honoring Lippmann's legacy very, very well. The manufacturing of consent continues, and invisible government remains invisible. Lippmann and Bernays (both journalists) had very similar views, see: this. Wheras Bernays talked about the Engineering of Consent, Lippmann talked about the manufacture of consent. They're largely the same, when you consider how much just doesn't get reported, or of what does get reported is favorable to those intelligent minorities (such as journalists) who know how to regiment and guide the masses.