Legally rigging elections?

State legislatures are using computer-aided gerrymanders to ensure that the dominant party stays in power. How does gerrymandering work? Here's everything you need to know: 

How does gerrymandering work?

Under the Constitution, state legislatures redraw congressional districts every 10 years to account for census-documented population changes. To ensure equal representation, these districts must be roughly even in population. But since the early 19th century, legislatures have often engaged in creative boundary drawing to guarantee that most congressional seats will go to the party in control of the legislature. As a simple...