And, my reading of some historical accounts is that Robert E. Lee initially refused to become commander of the Union army in the spring of 1861 because his first loyalty was to defend his state of Virginia, which was about to secede from the Union.
The name of the country was a plural prior to the Civil War: "The United States are entering into a treaty."
After the war, it shifted to a single entity: "The United States is entering into a treaty."
The difference was that most people identified with their state first, then the United States second. The current understanding for most people is to identify as an American first and their state of birth or state of residency second (if at all).
Except in Texas, where we are known for taking pride in being born in Texas, and those who were not so fortunate will proclaim, "I wasn't born in Texas but I got here as soon as I could."