In Magic there are several ways a powerful player can overcome politics, in large part because a player can choose their deck. This makes most sense to analyze in the case of repeat play among a stable playgroup. Here are three ways to do it:
Play a deck that is opponent-count agnostic such as combo. You need to play combos that go "infinite" (such as Exquisite Blood + Vito, Thorn of Dusk Rose) rather than combos that get you to 20 damage very efficiently (such as Channel + Fireball). Here, the skill is in piloting your deck, dodging two player's worth of removal, and setting off your combo before the aggro of two players can kill you.
Play a defensive flavor of control. This involves cards that that make it obnoxious for people to attack you, like Ghostly Prison, Lightmine Field, and Hold the Line. So long as you are not overtly offensively threatening, you can change the calculus for other players attacking you such that it isn't worth it. Your goal here is likely to get the game to go to a standoff that your deck has some way to win (such as a combo or milling opponents).
Play a deck that is worse. Reducing your threat, so long as you can publicly signal that you are doing so, will make two other rational players fight each other first. This has solid game theory foundations. See the Ted Ed Wizard Standoff for a game theoretical example.
Play a deck that leans into politics. There are many cards like Bazaar Trader, Phelddagrif, Zedruu the Greathearted, or even Howling Mine that can let you manipulate the state of the table to change people's priorities. As much as you may be the biggest threat in the abstract, if you can change it so someone else is the biggest threat in the concrete, that can change the focus of player's ire. Credit to @TimC for this point.
