I would say that Bannon was Tywin Lannister to Trump's King Aerys II, but....

[Tommy_Carcetti]

.....Charles Dance's portrayal was far too elegant and sophisticated to be confused with the hot mess that is Steve Bannon.

Besides, Tywin struck me as being a lot more saavy and calculating than Bannon would ever be.

Still, there's this:

Meanwhile, Aerys's relationship with his Hand was breaking down as well, the pair's friendship fraying. Where previously Aerys had heeded Tywin's counsel, he now often disagreed with his Hand and did the opposite of what Tywin suggested. When Myr and Tyrosh became involved in a trade war against Volantis, Lord Tywin suggested that Westeros remained neutral. King Aerys, in response, provided gold and arms to the Volantenese. When House Bracken and House Blackwood had a border dispute, Lord Tywin wanted to act in favor for House Blackwood, leading to Aerys siding with House Bracken. Over Tywin's objections, Aerys doubled the port fees for Oldtown and King's Landing and tripled them at Lannisport and other ports in Westeros. Trade suffered and a delegation of merchants arrived before the Iron Throne to protest. Aerys lied to them and blamed the matter on his Hand of the King stating;

“ Lord Tywin shits gold, but of late he has been constipated and had to find some other ways to fill our coffers.[2] ”

Aerys restored the port fees to the previous levels, which won him much popularity and acclaim for himself, whilst the king's lies and actions left Tywin with nothing but scorn. Aerys objected to many of Tywin's appointments and filled the offices with men of his own choosing. When Tywin suggested his own brother, Ser Tygett Lannister, as master-at-arms for the Red Keep, Aerys appointed Ser Willem Darry instead.[2]

By now, Aerys had become aware of the tales being told in his kingdoms; that it was Lord Tywin who truly ruled the Seven Kingdoms and that Aerys was but a hollow figurehead. These statements greatly angered the king. When Lord Tywin's captain of guard, Ser Ilyn Payne, had been overheard to repeat this statement, Aerys had the man's tongue torn out with hot pincers.[9][10] The angered king became determined to disprove the tales, and to humble Tywin, his "overmighty servant", putting him back into his place.[2]

http://awoiaf.westeros.org/index.php/Aerys_II_Targaryen

[anneboleyn]

1. Aerys was also once a highly charismatic and good king. Trump cant be compared to Aerys either

Aerys’s decline came much later in life, and those who were present during the first part of his rule said that he was an incredibly charming and loved king — like many of the Targaryens who aren’t afflicted with the “madness” that Dany worries about and for good reason.

When the paranoia and madness began to set in (I know there are some fan theories that Aerys was in fact being slowly poisoned, possibly by Lannister representatives, with the idea of replacing him with someone else — and not Prince Rhaegar). Trump never had any of Aerys’s culture, intelligence, or charisma so I can’t go for that comparison either. Trump is way, way too much of a transparent and egocentric buffoon to be compared to Aerys, who was a highly intelligent and elegant Targaryen until the madness stole all of that away, and yeah Tywin is nothing like Bannon. As you said, Tywin is not a “hot mess.” Never was under any circumstances — not even when facing Tyrion at that critical moment.

Honestly I can’t think of an apt comparison to Trump in Westeros — maybe one of the bombastic big money no class types in Essos would work better. Even the Boltons were better at strategy than Trump. Maybe Mace Tyrell? A buffoon born into a great (wealthy) family by dumb luck who wears flamboyant clothing, can’t ride his horse though he still pretends to be a knight like Jaime Lannister, and just shows up while the brilliant grandmother and granddaughter actually run the family and its political affairs?