We think of our country as a single, unitary nation. That wasn't always the case.
It may not strike us now as odd that we use "The United States" as a singular noun, but this wasn't always the way everyone spoke. Google N-gram data, which tracks words across Google Books, shows that in the mid-1800s, it was roughly as common to refer to the United States in the singular sense as it was to refer to the United States as a plural group of states that were united. It reveals a profound shift in how Americans think. In the late 19th century, Americans appear to have started thinking of the US as one big actor instead of many smaller ones.
A Princeton PhD, was a U.S. diplomat for over 20 years, mostly in Central/Eastern Europe, and was promoted to the Senior Foreign Service in 1997. After leaving the State Department in order to express opposition to the planned invasion of Iraq, he taught courses at Georgetown University pertaining to the tension between propaganda and public diplomacy. For many years he shared ideas on the theme "E Pluribus Unum? What Keeps the United States United" with Eurasian/European delegates participating in the "Open World" program.
Brown’s articles have appeared in numerous publications. A recent piece is “Janus-Faced Public Diplomacy: Creel and Lippmann During the Great War” (published in Nontraditional U.S. Public Diplomacy: Past, Present, and Future; now online).
He is the author (with S. Grant) of The Russian Empire and the USSR: A Guide to Manuscripts and Archival Materials in the United States (also online). In the past century, he served as an editor/translator of a joint U.S.-Soviet publication, The Establishment of Russian-American Relations, 1765-1815.