Gerrymandering is a deal with the devil. You need to be really sure of your polling. You theoretically get more districts with a majority for your party, but the majority in each of those districts is thinner than it was before. If something bad happens and there is a wave for the other party, you lose more seats than you would have otherwise.

And this is modern, post-gingrich gerrymandering.

Before that both sides worked together (mostly) to produce very safe districts.

People keep saying “they have been doing this forever “, but not like this.