Are we responsible solely for our individual decisions and actions, or do we also bear responsibility for group actions, the behavior and attitudes of those with whom we are affiliated in some way. This latter form of responsibility, if real, is a form of guilt by association. In other words to recognize and assign responsibility because of the actions of others, means that judgments can meaningfully be made by observing not only personal behavior but that of others with which I can be connected in some fashion. As noted before, judgment of others is fraught with possible errors; when we add to the mix the idea that judgments about an individual can be properly made by studying other people, the problems become even more acute. Despite that fact the idea of guilt by association is firmly imbedded in our minds and culture.
Undoubtedly, many will want to point to the Bible as justification for judging others and even for evidence that guilt by association is biblical. After all didn't Paul warn that evil companions corrupt good morals? Didn't God forbid the Hebrews from associating with the pagans who lived around them? We see strong evidence of the Jewish antipathy toward Gentiles in the actions of Peter, both in Acts 10 and in Galatians, not to mention the account of Jesus and the Samaritan woman at the well.
Of course, one of the most frequent and serious charges brought against Jesus was that he associated with sinners. The belief in guilt by association was very much a part of the mentality of Jewish religious leaders, and not without reason given what we read in the Bible.
But as in the case of judgment in general, the biblical record on guilt by association is confusing (Exodus 34:6-7, Ezekiel 18:19-20). In some places in the OT, guilt by association is taught. Then elsewhere, responsibility for one's own actions are said to be the basis for judgment. In both Testaments the concept of segregating from evildoers is promoted. That is true, even though, in the NT for sure, the segregators were asked to teach and convert unbelieving people, the very ones they are elsewhere commanded to avoid. Condemn, segregate, and convert as a conversion strategy makes no sense. It does, however, allow the church to make spiritual transformation a secondary priority, way behind promoting self righteousness and political intrigue.