Henry Spencer wrote:

There is actually room to argue about that. The US was "established" only
in the loosest possible sense before the ratification of the Constitution.
It resembled a single nation about as much as the CIS resembles one today.

Agreed. It's telling that before the Civil War, it was convention to refer to
the United States in the plural. Only after the war did Americans begin to
use the United States as a singular noun.

--
Dave Michelson