They might be political, but since their members are appointed for life, they don't have to worry about making career and making sure they stay in good favor with certain politicians, and having to win elections to stay at their job. They tend to take more of a long term perspective and don't usually get caught up in the 'political flavor of the day'.
Furthermore, the makeup of the supreme court is more balanced, with 3 conservatives, 3 liberals, and 3 "middle of the roaders". I think that's a nice balance, and that balance has shown itself in their decisions over the last few years -- nothing to extreme on either side, balance is good.
Besides, since EVERYONE is biased one way or the other, and the courts can't seem to keep their partisanship out of the way, things like elections should be decided the way the constitution set them out to be decided -- by the people, and if there was any doubts/conflicts, by those elected by the people, the legislature. Not the courts.