I have read parts. It seems an ill omen to me that he starts with Plato's image of the cave. Plato was NOT an advocate of the average person. He wanted to be the advisor to tyrants. Even the experience of being sold into slavery by one such tyrant who Plato was trying to advise did not dissuade Plato from his belief that only a ruler could see things rightly - if said ruler followed Plato's advise.

That I am on the right track with Lippmann is confirmed towards the end of chapter I when he states: "My conclusion is that public opinions must be organized for the press if they are to be sound, not by the press as it is today. This organization I conceive to be, in the first place, the task of a political science that has won its place as a formulator in advance of real decision instead of apologist, critic or reporter after the decision has been made."

Lippmann reifies the abstraction of 'Political Science' as some objective science. Political Science gives, in fact, about as successful and accurate description of the political process as US Mainstream Economics gives of the operation of the economy.  

"It is not necessary to have hope in order to persevere."