How can you find out to which political party a Supreme Court Justice belongs?

Answer 1

If there is no biographical information available that specifies the justice's party affiliation (and there often isn't), one clue would be identifying which President nominated him or her. The President typically chooses someone with an ideology compatible with his own, because that is the only influence the Executive branch can exercise over the Judicial branch - placing people who will evaluate the Constitution from a liberal, conservative, or centrist perspective.

This is not a foolproof method of evaluation, however. The most recent justice appointed to the Supreme Court, Sonia Sotomayor, was nominated by the Democratic President Obama, but is, herself, an Independent with a judicial history of centrism.

Unfortunately, matching a justice to a party doesn't necessarily tell you how that person will vote on a particular issue. Some justices change their personal ideology or jurisprudence over the years, often becoming more progressive the longer they are on the bench; and some justices may vote against their personal ideology if their personal beliefs conflict with a reasonable interpretation of the Constitution. This has been a source of frustration and dismay for some Republican Presidents.