Judges are supposed to be impartial but they're still just human. Moreover even when they are perfectly impartial (and the US is more lucky than they appreciate

Judges are supposed to be impartial but they're still just human. Moreover even when they are perfectly impartial (and the US is more lucky than they appreciate in how professional their federal judiciary is, particularly compared to the other branches) there are different kinds of judicial philosophies that can influence how laws are interpreted (which is particularly important since the US operates under a common law system) so these currents can be classified as broadly embraced by liberals/conservatives Aside from the other comment regarding who appointed the judges > chosen by the currently elected president whenever seats in the court become vacant This is incomplete, the judges are nominated by the executive but have to be confirmed by the senate Until recently (first Obama term I think) practically speaking a judge needed 2/3 of the senate to be confirmed, therefore in practice judges had an incentive to at least appear as moderate if they wanted to get eventually promoted. Now that they need just a simple majority this incentive is gone and, since courts have been progressively been forced by politicians to make decisions for them, it arguably is reversed since now presidents with a majority in the senate will want to propose the most partisan judge they can get through their own party and lower judges know this So probably it'll get worse