Robert A. Caro said this quote
“ No southerner had been elected President for more than a century, and it was a bitter article of faith among southern politicians that no southerner would be elected President in any foreseeable future; when members of the House of Representatives gave their Speaker, Sam Rayburn, ruler of the House for more than two decades, a limousine as a present, attached to the back of the front seat was a plaque that read 'To Our Beloved Sam Rayburn - Who Would Have Been President If He Had Come From Any Place but the South. ”