"Sa", as previously noted, is not an accepted Scrabble word. Abbreviations are not acceptable in Scrabble. Foreign words aren't accepted in Scrabble so "Ist" and, "Sa" would be out there as well as it appears we're playing English Scrabble. "Ra" is also not accepted in Scrabble as proper names (like, "Thor" for another example.) are not accepted.

https://wordfind.com/word/ra/

More importantly, words need to connect to an existing word so, "ra", and, "ist" by themselves wouldn't be accepted on those grounds, hence the determination that the person played them on their turn and is actively tying to figure out which letter they should use for the middle bit to finish the single word on a single line they can play on their turn.

https://www.scrabblepages.com/scrabble/rules/

And yes, we are overthinking a political comic ITT.