GWEN IFILL:

No matter what the polls tell us about how unpopular Congress is, 90 percent of them are reelected every time. It's no accident. Their districts are drawn that way.

For proof, look no further than the state of Florida. Last month, a federal judge said two key districts there designed to protect the incumbents representing them were illegal. So, yesterday, the state legislature came up with new maps, two weeks before the next round of primary elections, and even though a million voters have already cast ballots.

Florida is not the only state where the lawmakers from both parties have stretched the limits of geography to create politically homogeneous districts.

Here to explain what's up and why is NewsHour political editor Domenico Montanaro.

So much of what happens, Domenico, in the midterms doesn't have to do with what voters themselves are voting for directly.