What does this tweet (from 10 minutes ago) mean?

First of all, I don’t think Trump gets the “Game of Thrones” reference.
Secondly, what sanctions? With Election Day on November 6, this sounds like a stunt.
UPDATE: Oh, okay. He’s talking about Iran sanctions.
Joffrey grew up. https://t.co/hpL8fjze0j
— Full Frontal (@FullFrontalSamB) November 2, 2018
A nice retort from Game of Thrones’ Arya:
Not today. https://t.co/Jg51mGHPO1
— Maisie Williams (@Maisie_Williams) November 2, 2018