Lippmann rejected his earlier socialism in Drift and Mastery (1914) and in 1916 became a staunch supporter of [[Woodrow Wilson]] and the Democratic Party. In 1917 Lippmann was appointed as assistant to [[Newton Baker]], Wilson's secretary of war. His role was propaganda. Lippman worked closely with [[Woodrow Wilson]] and [[Edward House]] in drafting the Fourteen Points Peace Programme. He was a member of the USA's delegation to the Paris Peace Conference of 1919 and helped draw up the covenant of the League of Nations.
It was his experience as a propagandist which convinv=ced convinced him of the possibility and the necessity to use propaganda and PR to manage popular opinion. His most remembered contribution was to coin the phrase [[Manufacture of consent]] - a phenomenon of which he approved.
In 1920 Lippmann left the [[New Republic]] to work for the [[New York World]]. His controversial books, Public Opinion (1922) and [[The Phantom Public]] (1925), raised doubts about the possibility of developing a true democracy in a modern, complex society.