Bureaucrats are people who say that if they don’t record a tree falling in the forest, that it didn’t happen. Scholars are people who believe in what bureaucrats record. Anecdote: My mother was born in Mississippi around the year 1910. The state did not then issue birth certificates. She grew up, married and then divorced a husband whose name she took. No official record exists of either event. She married my Dad and took his name, By that time she had long since shed her name given her by my grandmother, who was divorced from her father and had remarried. A record exists of the latter but not the former. When my mother became 62 and wanted to get social security benefits, she had to PROVE her age, first of all by proving through the census records that she ever existed. Nope. She had to go to her high school records to establish her claim. Luckily, she HAD gone to high school, because none of her elementary school records existed any more.
NOW, if it was there was so little documentation of an American life, what about the millions of Arabs who have lived in what is now Palestine?
What Peters did was go into the bureaucrats’s archives and find their memos that recorded the fact that they knew the in-migrants were in fact pouring over the border. Especially from the north.