In keeping with a custom begun by Lincoln in 1863, U.S. Presidents had declared a general day of thanksgiving to be observed on the last Thursday in November. By late October of that year, President Roosevelt decided to deviate from this custom and declare November 23, the second-to-last Thursday, as Thanksgiving that year. --Ace quoting Wiki
Whaddya know. Retailer greed accomodated by a Progressive/Lefty Democrat! Who'd a-thunkit?
A lot of states -- Republican-controlled -- refused to follow Franklin's diktat and observed Thanksgiving on the regularly-scheduled day.
Texas was right. You can smell the LBJ influence in the 1956 change.