If we could go back in time and do it from scratch, I like Germany's model for how they do it...
From my post in another thread:
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The more I've looked into it, the more I like what Germany has with their MMP system (Mixed Member Proportionality)
From my understanding (and any Germans on here, feel free to correct any misinterpretations I have)
German voters get two votes on their ballot. The first vote is for a local candidate in their district (like the US system), and the second vote is for a political party.
The final composition of their parliament must match the proportional party vote.
So half of legislature is populated by regional winners, and the other half is assigned by party leadership for the "filler seats" based on who needs to get what to make the numbers line up.
So, how that would work would be... (let's pretend the number is 700 just to keep the math easy)
350 of those seats would be populated by the regional winners, the other 350 would be assigned seats by party leadership.
Each "district" would be about 950,000 people (the states can divvy those up how they'd like, because gerrymandering would be a non-issue)
The results come in...
195 Republicans Won the local races, and 155 Democrats won local races
The party vote came in, and 53% of voters said "D", and 47% said "R"
How that would shake out for the "proportionally ensured seats"
- Democrats need: 371 total - 155 won = 216 proportional seats
- Republicans need: 329 total - 195 won = 134 proportional seats
That system not only makes gerrymandering "moot" in terms of unfair advantage, it actually make gerrymandering a liability if someone tried it.
If a party drew some wacky looking districts just to help a few specific guys get a victory, they'd actually be handing more proportional seats to the other party's leadership to assign (not elect), so there's almost an incentive to keep districts as proportional as possible, because you can strategize to beat someone in an election, there's no strategizing if the other party's leadership can pick whoever they'd like to fill a seat.