Mere America is a novel that takes place in an alternate America, one in which the New World is geographically reversed east-to-west relative to Eurasia and Africa. Why the name Mere America?
Firstly, the colonists from Europe had a much tougher time of it in North America. They had to contend with the Rocky Mountains instead of the Appalachians; and while the southern portion of the coastline had a pleasant climate and was wealthy in gold, it was also dry and difficult to farm. One result of this is that the United States is a much smaller country; so in that sense, America is mere.
Secondly, the word mere calls to mind the word “mirror”, which is apt since the geography of America is mirror-reversed. There are other reversed things in this scenario: for example, Richard Nixon is the first president of a communist nation to visit the United States, rather than the first US President to visit a communist nation (China).
A great deal of world building for the novel is done, including carefully worked-out military, economic, and social changes, and elaborate family trees of important characters (especially the Dare family of Virginia). You can read some of it at this old creaky blog. I will definitely return to this magnum opus one day, but right now it’s rather low priority.