Here is how the BoardGameGeek link above explains it how it is different from regular Scrabble:
All of the extra scoring spaces are replaced with the various states. They have two effects. The give the familiar triple letter or triple word scoring bonus. In addition each states gives an additional bonus equal to the state’s Electoral College value (after all other modifications). So for instance California is a triple letter space and gives a bonus of 55 points as well (it is also way off to one side). There is a list of extra “words” that are worth extra points; either 5, 10 or 15 points. Some of these “words” are things like FDR or LBJ which would not ordinarily be available to use, while others are regular words like vote that just give an extra bonus.
Finally there is a deck of cards showing all of the Presidents. Each card has a bit of historical information and gives a way to either get an extra bonus when played or change the rules in some fashion. The Nixon card for instance allows one to play a word with one letter misspelled. Players receive five of these cards at the start of the game, and can play at most one per turn.
My favorite part of the link, though, is this part:
The board is round and not square.
I love it because nothing more is said on it. Why is it round and not square? I have no idea. I guess they thought it would look cooler if it wasn’t just the round Great Seal of the United States on a square board or square Scrabble grid inside the circle?
There’s a reason it was in Goodwill.