[dmix]

Indeed, the previous time the US Supreme Court was dealing with gerrymandering rules/tests it was a republicans accusing the democrat's of unfair gerrymandering in Maryland: https://www.supremecourt.gov/opinions/17pdf/17-333_b97c.pdf

Then the latest one was democrats challenging republicans in Wisconsin.

It has a long complicated history of courts and politicians trying to balance the lines. As long as there's a way to game the system in your favour, someone will try - regardless of party.