|The Hebrew term "Tzdakah", often translated as "social justice" in non-Jewish languages, actually just means justice - a shorthand for "deal with every man as he deserves", and "judge and stand ready for judgement." Since Judaism has no concept of "charity" ("caritas") in the Christian sense, there is a tendency to translate the Hebrew in a way that will appeal to Christians as similar to caritas. To get a sense of what tzdakah means in Jewish ethics, consider the following from Maimonides:|
"What are the best ways to do tzdakah to a poor person?
The best is to create a job for him by investing in a business, so that he will be able to support himself by working.
The second-best is to teach him a skill, so that he will be qualified to compete for an already existing job." etc.
Note that tzdakah, unlike caritas, does not ever imply that there is anything good about giving undeserved support to someone who is poor because he is not willing to work, not willing to learn a skill, or anything similar.
In modern times, there have been Kantian and other collectivist interpretations of Jewish ethics, and general assimilation into the prevalent culture. In Central Europe, where most Israeli and American Jews came from, the prevalent culture was heavily socialist, and Jews from Central Europe brought their assimilated socialism with them. The counterweight to this tendency is that Jewish culture encourages intellectual independence, so that in formerly socialist cultures Jews are usually the first to discard socialism. But on the other hand, intellectual independence does drive one to greater consistency, so a Jew who has not yet discarded socialism will tend to be a declared socialist, and not a wishy-washy middle-of-the-road "leftist liberal." On yet another hand, this also means that Jews become libertarians and not moderate conservatives, atheists rather than agnostics, etc.