Ross Ramsey in the Texas Tribune:

Some people think it’s unfair to have more eligible voters in one legislative district than in another — that basing things solely on total population is the wrong way to draw political maps. But that’s only one way the lines might be seen to slight a particular group of Texans.

The question stems from a lawsuit that went to the U.S. Supreme Court this week challenging the current maps for Texas Senate elections. The plaintiffs argue that those maps — drawn to put approximately the same number of people in every district — put them at a disadvantage by including unequal numbers of eligible voters in each district.

Those districts were drawn according to total population instead of the number of people who are eligible to vote. In the Evenwel vs. Abbott case argued this week, two Texas voters said their votes are diluted because Texas Senate districts have the same populations, but not the same numbers of voters. Each voter has a louder voice in districts with relatively fewer voters.

But the number of eligible voters in each district is far from the only difference that might matter to Texans, whether they vote or not.