The Supreme Court isn't comprised of politicians. That's something only those that haven't had the benefit of legal study or those who believe in domestic realpolitik and its attendant influences think. In fact, the Court's decisions are replete with an almost crazy fidelity to stare decisis, the prudential doctrine stating that they won't overturn cases unless they fundamentally have to. They'll whittle around the edges, say that certain tests should be weighted certain ways, that different phrases have different definitions that don't keep with historical meaning (like in Kelo), but they generally do not politicize or overturn cases. In fact, some of the judges' political dispositions aren't in keeping at all with how they view the law or the constitution and their judgments and opinions stem from not a politicized place, but rather, a philosophical one regarding how they understand the laws to have come amount and what they extend to, to the best of their abilities, properly understood.
To say that they're politicians with robes undermines the legal mission and the Court's. It is not necessarily so. In modern times, Justice Douglass was the closest to ever becoming a rogue politician on the bench (it is no accident that he is the one who "discovered," within the Constitution, the intellectual grounds for the right of privacy and abortion) and was almost impeached for erratic behavior in the early seventies. Brennan and Marshall were also considered heavily indebted to policy concerns on the bench at that time, but to call them mere politicians is to denigrate their legacy as jurists worthy of reading and understanding. That their opinions often hinge on what Cardozo called "The Sociological Method" is a reason to study policy and legal realism vs. legal formalism, intent, and logic and see where one stands on that issue.
But politicians in robes, no.