The recent Supreme Court decision, to keep the federal judiciary out of the business of how to draw the boundaries of legislative districts, strikes me as a move in support of a free political market. Why try to figure out what a fair market might look like? Let the market decide what is fair! But the problem with anarchy is that it is impossible. We can decide on rules using methods developed over the centuries and codified by brilliant political thinkers like the framers of the United States Constitution, or we can revert to the cruder methods of tyrants.
Of course the framers didn't provide all the answers. We the people have the responsibility, working with the general framework set out in the constitution, to work out the rules and regulations, the laws and institutions, by which we may prosper fairly and equitably.
It's clear enough that legislative boundaries can be gerrymandered to amplify the dominance of whichever party. Even if some branch of the government took on the task of preventing such corruption, it's not so clear what kind of rule could work against it effectively. I would like to propose a rule here that could work.
The basic trick used in gerrymandering is to concentrate the voters of the minority party. The voters of the majority party are spread across districts, so there are just enough to win in a very large number of districts.
So here is an effective anti-gerrymandering rule: for each x, there cannot be more districts with more than (50+x)% minority party voters than there are districts with more than (50+x)% majority party voters.
In other words, minority party voters cannot be concentrated in districts more than majority party voters are.
This is a simple rule that would prevent the worst abuses of gerrymandering.