I have written this oped on Evenwel for the LA Times oped page. It begins:
At the Supreme Court on Tuesday, the justices struggled over the meaning of the 1960s-era “one person, one vote” rule. Should Texas legislative districts contain an equal number of people — as they do now — or an equal number of eligible voters, as the plaintiffs in Evenwel vs. Abbott demand? Ultimately, the justices may have no choice but to heed some other words written in the 1960s: You can’t always get what you want.
At the oral argument Tuesday, Justice Anthony Kennedy tried to split the difference. He pondered whether Texas — and other states — could draw districts with an equal number of people and an equal number of voters. “Why can’t you have both?” he asked Texas Solicitor General Scott Keller.
And this is where the Rolling Stones principle comes in: A total population standard isn’t what everyone wants, but it’s what we need to avoid chaos.
A legislative map equalizing both total voters and total population would violate all sound redistricting principles, breaking up cities, separating communities of interests and producing grotesque shapes. Indeed, after Keller made these points, Kennedy seemed to concede the point: “That sounds highly probable to me.”
An attempt to equalize both population and voters would have especially bad consequences for minority representation. In a forthcoming paper Vanderbilt law and mathematics professor Paul Edelman shows that it is mathematically possible to draw districts that equalize both voters and population — but only at a big cost. He concludes that “dual districting may well be antithetical to achieving majority-minority districts,” a cornerstone of the Voting Rights Act.
It’s also impossible at this point to reliably draw districts with an equal number of voters. As Nathaniel Persily of Stanford Law School has argued, we simply don’t have the data to do it.