How would you define a fair division? One that makes the parties win 50-50? The question and options go deeper.
If the Democrats in those right leaning districts move further to the right, they could pull off some centrists. The next question is how many voters actually read local party or candidate platforms, and how many just show up and vote for the (Dem) or (Rep) and leaven without thinking.
I designed a voting system that takes care of all that without worry how the districts are drawn. California has a prototype version. They put several candidates on an open primary. All voters of all parties vote for 1 candidate. The top 2 go the general election, even if it is 2 democrats or 2 republicans. The intent is to elect moderates who hold the average values of that district, so that gerrymandering does not matter as much.
Top 2 failed in Oregon by 2:1. The unstated reason, I think, is parties don't like having their primaries open. In California, there were races with 10 candidates in one party split each other's vote, throwing the race to the other party. They still got to pick between that party's 2 candidates.
My solution to get it passed and avoid vote splitting is to only allow 4 candidates on the general ballot, with the top 2 getting a runoff. 4 is small enough to avoid vote splitting. Let the parties hold private conventions. To get on the ballot, you need to find people who donate $5 to your campaign, not just sign a petition. All candidates should have to do this, with or without the help of a convention, and the top 4 with the most $+5 donors get on the ballot.
The key to beating gerrymandering is to give the moderates a chance to represent the district. The current closed primary system just leads to candidates running unopposed.
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