The Golden Dawn gave Justice the letter Lamed, the sign Libra, and the twenty-second path of the Tree of Life, from Geburah to Tiphareth. Lamed is an ox-goad, an instrument of correction, and Libra is the scales, so the assignment is one of the least strained in the system. Like all of them it is late nineteenth century and follows Eliphas Levi's earlier arrangement of the 1850s rather than any medieval source.
In practice this is a card most readers soften and probably should not. Its plain sense is that a matter will be decided on its merits, that the decision has already been earned by what was done, and that the querent's preferences are not an input. Where the sword and the scales are read together, the card says that a judgement will be both weighed and enforced.
The gentler modern readings, balance, fairness, harmony, integrity, are not wrong, but they blur the card into Temperance and cost it its edge. The more exact readings run to legal matters, contracts, consequences arriving on schedule, and the specific discomfort of being treated exactly as one has behaved.
Waite's reversed meanings run to legal complications, bias and undue severity, which are useful and specific. Readers who do not turn cards read the same range by asking who is holding the scales in the situation described, and whether that person is the querent. Crowley's version, retitled Adjustment, drops the moral vocabulary entirely and treats the card as the universe balancing its books, which is arguably closer to what readers actually observe.