4th July question - what is America?

Today is the 4th of July when Americans celebrate their rebellion. A friend sent me this quotation from my beloved Dr Johnson.

To a man of mere animal life, you can urge no argument against going to America, but that it will be some time before he will get the earth to produce. But a man of any intellectual enjoyment will not easily go and immerse himself and his posterity for ages in barbarism.

He of course was talking about the America of his day, largely savage. 

A.J.P. Taylor said we visit countries for architecture and food and America has neither. Again be understanding, gentle American reader. He meant, of course, old buildings and a national cuisine. He also speculated that if

the Germans had succeeded in exterminating their Slav neighbors as the Anglo-Saxons in North America succeeded in exterminating the Indians, the effect would have been what it has been on the Americans: the Germans would have become advocates of brotherly love and international reconciliation.

I reread Thomas Love Peacock's last conversation novel, Gryll Grange (1861), last year and came across Dr Optimian arguing that to America 

we are indebted for nothing but evil; diseases in the worst forms that can afflict humanity, and slavery in the worst form in which slavery can exist. The Old World had the sugar-cane and the cotton-plant, though it did not so misuse them. Then, what good have we got from America? What good of any kind, from the whole continent and its islands, from the Esquimaux to Patagonia?

Mr. Gryll. Newfoundland salt fish, Doctor.
The Rev. Dr. Opimian. That is something, but it does not turn the scale. 
Mr. Gryll. If they have given us no good, we have given them none.
The Rev. Dr. Opimian.  We have given them wine and classical literature; but I am afraid Bacchus and Minerva have equally  "scattered their bounty upon barren ground". On the other-hand, we have given the red men rum, which has been the chief instrument of their perdition. On the whole, our intercourse with America has been little else than an interchange of vices and diseases.

Lord Curryfin. Do you count it nothing to have substituted civilised for savage men?
The Rev. Dr. Opimian. Civilised. The word requires definition. But looking into futurity, it seems to me that the ultimate tendency of the change is to substitute the worse for the better race, the Negro for the Red Indian. The Red Indian will not work for a master. No ill-usage will make him. Herein, he is the noblest specimen of humanity that ever walked the earth. Therefore, the white man exterminates his race. But the time will come, when by mere force of numbers, the black race will predominate, and exterminate the white. And thus the worse race will be substituted for the better, even as it is in St. Domingo, where the Negro has taken the place of the Caraib. The change is clearly for the worse.

Lord Curryfin. You imply that in the meantime the white race is better than the red.
The Rev. Dr. Opimian. I leave that as an open question. But I hold, as some have done before me, that the human mind degenerates in America, and that the superiority, such as it is, of the white race, is only kept up by intercourse with Europe. 

It seems to me that although America is not an ethnic state (though it was something like one in 1783, excepting the slaves) the USA is not 'a proposition nation'. The men who created the USA were British and American culture and identity is still at its core Anglo-Saxon. Eighteenth century British Whig ideas are therefore very important, as the Tories were ethnically cleansed and then written out of the history books, but they are certainly not the essence of what America is. Ann Coulter said black Americans are Anglo-Saxon too. 

I wrote about this three years ago:

G.K. Chesterton said in 1921

'America is the only nation in the world that is founded on a creed.' 

The US's House Speaker Paul Ryan, a Republican, thinks so. He told interns in Congress this week that

'America is the only nation founded on an idea not on an identity.'

But is that right? Forty years after the American declaration of independence the South American republics were founded by deists and Freemasons.... (Continued here.)