and tonight a closer look at a battle that could shift the balance of power in this country for the next decade. i'm talking about redistricting and the often legal rigging that occurs when partisans in state houses intentionally distort maps to keep themselves in power, a practice known as gerrymandering. dana bash takes us to texas, one of the most heavily gerrymandered states in the nation. >> reporter: we're in downtown austin. >> yes. >> this is an area that right now is represented by a republican. it's going to change with the new lines. >> it is. it is. >> reporter: austin, the capital of texas, is a pretty liberal town. it's a key reason republicans drew new congressional maps that took city blocks like this and progressives who live here out of their gop districts. >> here in austin, what the republicans did was pack as many democrats into as few districts as possible. the republican districts are not only just going to be republican, they're going to be