" Do you think the United States is currently a united or a divided country? If you are like most people, you would say the United States is divided these days due to the high level of political polarization. You might even say the country is about as divided as it has ever been. America, after all, is now color-coded: red states are Republican; blue states are Democratic. But, in Uncharted, Aiden and Michel note one fascinating data point that reveals just how much more divided the United States once was. The data point is the language people use to talk about the country. Note the words I used in the previous paragraph when I discussed how divided the country is. I wrote, “The United States is divided.” I referred to the United States as a singular noun. This is natural; it is proper grammar and standard usage. I am sure you didn’t even notice. However, Americans didn’t always speak this way. In the early days of the country, Americans referred to the United States using the plural form. For example, John Adams, in his 1799 State of the Union address, referred to “the United States in their treaties with his Britanic Majesty.” If my book were written in 1800, I would have said, “The United States are divided.” This little usage difference has long been a fascination for historians, since it suggests there was a point when America stopped thinking of itself as a collection of states and started thinking of itself as one nation. "
― Seth Stephens-Davidowitz , Everybody Lies: Big Data, New Data, and What the Internet Can Tell Us About Who We Really Are