Sometimes trying to understand the relationship between the decanic minors and the associated zodiacal majors (planet and sign) can be quite tricky, for example with the X of Swords in Gemini III which is enigmatically associated with the Sun and The Lovers. However, with the II of Swords it seems pretty straight-forward. If there was a slider with The High Priestess on one end and Justice on the other, the exact midpoint between the two would be the II of Swords. T. Susan Chang calls the II of Swords the "Little Priestess", and it's easy to see why.
Another interesting thing T. Susan Chang points out in 36 Secrets is that each of the twos fall either on a solstice or an equinox. This makes perfect sense as the tropical zodiac is pinned to the movement of the sun (or the earth's rotation around the sun, to be more precise) and the tarot minors are just overlaid on top of the tropical zodiac wheel, but this layout of the twos wasn't something I had really considered before. The II of Swords, as the first decan of Libra, lands on the autumnal equinox and marks the beginning of longer nights and shorter days (in the northern hemisphere anyway). Given the strong theme of balance in the II of Swords, this also makes sense.
For me, the II of Swords is all about internal balance and fairness. The majors represent the epic greater-than-the-self themes, while the minors are represent the self and the day-to-day themes of human life. The II of Swords is a reminder to make space for other perspectives (swords/mind/words) and to strive toward balance, even when everything else is going to shit.