From the Washington Examiner: 
Recommended for further reading is a paper last October by John Maxwell Hamilton and Kevin R. Kosar for the R Street Institute: “Government Information and Propaganda: How To Draw A Line ?” The paper has examples ranging from Woodrow Wilson’s wartime mobilization of public opinion to more recent Cabinet department advocacy of minimum wage hikes and Obamacare. Because judicial remedies are few, they note that vigilance by Congress, including budgeters, can be vital in monitoring the floodgates. And they quote law professor and First Amendment expert Geoffrey Stone:
As a constitutional matter, we tend to give broad leeway to the government’s own propagandizing, and there is not judicial precedent declaring government speech itself unconstitutional under the First Amendment. But even if there is no constitutional barrier to government advocacy of its own policies, there are certainly limits on how far the government should go. The line between responsible advocacy and irresponsible manipulation of public opinion may not be legally enforceable, but it is critical as a matter of sound governance.
- “Washington Examiner:”: https://www.washingtonexaminer.com/opinion/the-epa-will-keep-funding-the-chesapeake-bay-journal-should-it
- “Government Information and Propaganda: How To Draw A Line”: http://www.rstreet.org/wp-content/uploads/2016/11/73.pdf