Today, US Attorney General Jeff Sessions thanked sheriffs as a defining institution in the “Anglo-American heritage.”
I want to thank every sheriff in America. Since our founding, the independently elected sheriff has been the people's protector, who keeps law enforcement close to and accountable to people through the elected process," Sessions said in remarks at the National Sheriffs Association winter meeting, adding, "The office of sheriff is a critical part of the Anglo-American heritage of law enforcement." [source]
Slip of the tongue or otherwise, his use of the term reflects a particular worldview as he is evoking the image of America today as reflecting the character and whiteness of the first colonists, who later came to be referred to as WASP.
It was this self-helping race of Englishmen that matched their wits against French official schemes in America. We may see the stuff they were made of in the Devonshire seamen who first attempted the permanent settlement of the new continent. For a time all that was most characteristic of the adventurous and sea-loving England was centered in Devonshire. Devonshire lies in the midst of that group of counties in the southwest of England in which Saxon ancestry did least to destroy or drive out the old Celtic population. There is accordingly a strong strain of Celtic blood among its people to this day; and the land suits with the strain. Its abrupt and broken headlands, its free heaths and ancient growths of forests, its pure and genial air, freshened on either hand by the breath of the sea, its bold and sunny coasts . . .
The author, Woodrow Wilson, wrote the above in his 5-volume work, A History of the American People, published in 1902. His classification excluded most European populations, and on that he wrote about an 1890 census which taxonomized the population of the US quite bitterly:
Immigrants poured steadily in as before, but with an alteration of stock which students of affairs marked with uneasiness. Throughout the century men of the sturdy stocks of the north of Europe had made up the main strain of foreign blood which was every year added to the vital working force of the country, or else men of the Latin-Gallic stocks of France and Northern Italy; but now there came multitudes of men of the lowest class from the South of Italy and men of the meaner sort out of Hungary and Poland, men out of the ranks where there was neither skill nor energy nor any initiative of quick intelligence; and they came in numbers which increased from year to year, as if the countries of the south of Europe were disburdening themselves of the more sordid and hapless elements of their population.
In other words, countries were not sending over their best and brightest, if they were even capable of producing quality individuals. As Christopher Hitchens succinctly puts it:
[Wilson’s] objection was to the dilution of Anglo-Saxondom. This confusion, between America’s need for labor and the revulsion of the Protestant Establishment toward certain kinds of immigrant, has taken many forms down the years. But whether it is an objection to Jews, Catholics, Chinese, Japanese, lumpen elements, or fifth columnists, it has always had some bearing on the Anglo-American “special relationship.” [source]
For what it’s worth, on the other side of the Atlantic there was considerable agreement in this respect:
In a memo to the British War Cabinet in late 1917, Sir Robert Cecil kept up the great tradition of his family’s arrogance by writing: “If America accepts our point of view . . . it will mean the dominance of that point of view in all international affairs.” He added that “though the American people are very largely foreign, both in origin and in mode of thought, their rulers are almost exclusively Anglo-Saxons, and share our political ideals.” It might seem unfair to make someone even as senior as Cecil into a representative figure (when cautioned by the American ambassador to remember the Boston Tea Party, he replied with composure that he had never been to Boston, nor graced a tea party in that fair city), but he was not unrepresentative either. In his regard for the trinity of blood, ruling class, and empire he took a standard Anglo-Saxon position.
It was at the beginning of the 20th century that Anglo-Saxondom was becoming something more like what Mr. Session was evoking above.
By mutation through war and overseas commitment, the old Anglo-Saxondom had in fact turned into a whitish version of “America First,” with a generally less sentimental attitude toward “the old country” except when rhetoric might by occasion demand otherwise.
There's of course a lot more history behind the term, but this is the essence, the hard core of what the US Attorney General invoked today.