Politics is (if systematically grounded, which for many individuals it probably isn't-and this isn't a statement about one faction or another, it is true across factions) necessarily downstream of a moral/ethical value framework. If that is a consequentialist framework, it necessarily also requires a world model. If it is a deontological framework, a world model may or may not be necessary.
> And the two predominant world models are giving very different predictions, right?
I...don't agree with the premise of the question that there are "two dominant world models". Even people in the same broad political faction tend to have a wide variety of different world models and moral frameworks; political factions are defined more by shared political conclusions than shared fundamental premises, whether of model or morals; and even within a system like the US where there are two broad electoral coalitions, there more than two identifiable political factions, so even if factions were cohesive around world models, partisan duopoly wouldn't imply a limitation to two dominant world models.