“Gerrymandering” has been defined as a process by which politicians choose their voters, rather than the other way around.
California is an example of gerrymandering on an international scale.
On a more practical note, Conservatives do not put as much effort into pre/post voting periods as do the Democrats. They actively plan, advertise, and even cultivate their leadership. Democrats rabble rouse, demonstrate, and infiltrate. Republicans do very little or none of that. Why is it a surprise that liberals take more ground?
If Conservatives really want things to be different, they need to become active in every way. I tried to get a Republican action committee set up in my end of Georgia; however, everyone was positive that angry blogging on FreeRepublic would somehow affect governance.