Fischer's only allegation is that the original English settlements on the East of North America (in what became the 13 original colonies) were settled in this way. He does not claim the same thing obtains as you move West.

In fact, tracing the ancestry of presidents, he finds that the majority come from only one background--the Borderers (border of Scotland and England) --who have an exaggerated sense of honor, place much emphasis on the extended family, place not much value on education, and believe in solving problems with violence. George Macdonald Fraser makes a similar point on the first page of Steel Bonnets--at the inauguration of NIxon--with Johnson and Graham in attendance--representatives of 3 of the roughest Border families.