I was taught as a girl that justice as a concept was the idea that good societies had a responsibility to hold all citizens accountable to lawful conduct and behavior. I was taught that it was morally wrong to discriminate against anyone based on age, gender, ethnicity or any other kind of social distinction. I was taught social justice is about making sure the laws protected everyone equally and held everyone accountable for their actions likewise equally. I am so grateful to my parents and grandparents for teaching me to believe these things not only in words but how they themselves treated everyone around them.
When tarot came into my life and I saw the Justice card, I felt strongly that same message. And to this day (maybe more than ever), this idea of justice as something for everyone equally, giving equal protection and demanding equal accountability comes straight into my heart every time the Justice card appears in a reading.
Justice sits between two pillars but they are not the same as those in the High Priestess according to Waite himself and don't relate to the Tree of Life the same way (though the sphinx in The Chariot do). I personally see a lot of attributes I associate with Geburah in Justice, especially in the way she holds up her sword. I can easily picture it flashing down and cutting into a situation (or person) in order to create justice out of inequity. I see Justice as lacking compassion but also lacking malice. Creating equality and demanding lawfulness isn't a gentle process.
Justice wears the red robes that make her a force of dynamic intensity with gold trim, crown and tools that symbolize her relationship with the Divine. She enforces the Laws which come from a higher place, imo. A place where all those things I was taught as a little girl come from and extend beyond any specific philosophical or spiritual doctrine.
Now, interpreting Justice in a reading can be very, very complicated. Its all about the context of the question, where Justice is positioned, and what other cards are there. But my fall back in interpretation is my belief that Lady Justice represents the archetype of a beyond human self-motivation to protect everyone equally and hold everyone accountable for their actions likewise equally. So I help myself or querents look at situations and figure out who, what, where when is there a need for more protection and/or more accountability.