The Supreme Court will answer a key question about the meaning of "one person, one vote."

Legislative districts must have roughly equivalent populations. That's been Equal Protection law for a long time. But how do you count the population? Do you include all residents or just those who are eligible to vote � or are states free to use either count?

Almost all state and local governments draw districts based on total population. If people who were ineligible to vote were evenly distributed, the difference between counting all people or counting only eligible voters would not matter. But demographic patterns vary widely.

If the challengers succeed, the practical consequences would be enormous, Joseph R. Fishkin, a law professor at the University of Texas at Austin wrote in 2012 in The Yale Law Journal.

It would, he said, �shift power markedly at every level, away from cities and neighborhoods with many immigrants and many children and toward the older, whiter, more exclusively native-born areas in which a higher proportion of the total population consists of eligible voters.�

"One person, one vote" sounds like a reference to the voters, but that phrase comes from the court cases, not the Constitution itself. You could also think in terms of equality in the number of persons each representative represents. And if we're going to think in terms of voters, why would we look at the number of persons eligible to vote as opposed to the number of persons who actually vote? We know that voter turnout varies geographically.

"It is easy to read the Supreme Court�s 5-to-4 decision in Alabama Legislative Black Caucus v. Alabama and Alabama Democratic Conference v. Alabama as a mostly inconsequential case..."

"... giving a small, and perhaps only temporary, victory for minority voters in a dispute over the redrawing of Alabama�s legislative districts after the 2010 census," writes Richard Hasen at SCOTUSblog.

Indeed, although the Supreme Court sent this �racial gerrymandering� case back for a wide and broad rehearing before a three-judge court, Alabama will be free to junk its plan and start over with one that may achieve the same political ends and keep it out of legal trouble. But Justice Antonin Scalia in his dissent sees the majority as issuing �a sweeping holding that will have profound implications for the constitutional ideal of one person, one vote, for the future of the Voting Rights Act of 1965, and for the primacy of the State in managing its own elections.� Time will tell if Justice Scalia�s warning against the implications of what he termed a �fantastical� majority opinion is more than typical Scalian hyperbole....

 ADDED: Here's the PDF of the opinion, which I can't read just yet.

"Let�s talk about today�s argument in Arizona State Legislature v. Arizona Independent Redistricting Commission in Plain English."

Amy Howe has a readable summary of the complicated problem of independent redistricting commissions and the Constitution's Elections Clause("Times, Places and Manner of holding Elections for . . . Representatives, shall be prescribed in each State by the Legislature thereof"). Howe's penultimate sentence:

[S]upporters of the commission warn the Court that, if voters aren�t allowed to hand responsibility for redistricting over to independent commissions like the ones in Arizona and California, there will be no real way to combat political gerrymandering, which results in �partisanship and dysfunction� in Congress.

Obviously, there's another side to that. The "real way to combat political gerrymandering" could be the way provided for in the text of the Constitution: the legislative process.