>We just had an election in Alabama that proved this view incorrect. Even in seemingly "safe" districts your vote can matter. That's how safe districts become safe.

It's kind of counter-intuitive, but the election of a Democrat in Alabama actually provided a lot of discouraging data about gerrymandering. While a Democrat won the state-wide popular vote, if those votes had been cast in the House districts, Republicans would have won six of the state's seven seats. Gerrymandering doesn't really help as much in a Senate race, but in House races, it's everything.