The following is a guest post from Bill Whitford, a retired law professor at the University of Wisconsin and the lead plaintiff in Gill v. Whitford:

Richard Pildes recently suggested that while the Supreme Court may begin subjecting partisan gerrymanders to constitutional restraints, it will require an evaluation of partisan excess that proceeds on a district-by-district basis.  In our case, Gill v.Whitford, we have proposed a statewide analysis that compares statewide votes to seats.  At first glance it may appear that a district-by-district approach would be a less intrusive limitation on what has traditionally been a legislative function (redistricting).  In fact, a district-by-district approach will involve the courts in many of the problems that historically made them reluctant to place constitutional restraints on partisan gerrymanders, and to a much greater degree than if the courts proceeded on a statewide analysis.

A district-by-district approach to state legislative apportionments invites proponents of the disadvantaged party (Democrats in Wisconsin) to challenge many districts, in order to flip party control in the legislature.  The latter is the only thing that really matters in determining legislative output.  That in turn is going to place a tremendous burden on trial courts, all of whom will be three judge district courts.  Either there will be many separate cases, or one massive case involving many districts (at least 20 districts in Wisconsin).  Each case will have to get into the details of how the district lines of particular districts were chosen, what alternatives were rejected, and so forth.  I can easily imagine two days of trial time per district (one day per side to present evidence), but suppose we cut that estimate in half.  That still leaves a 3 to 4 week trial, with three judges who will not be able to work on other cases during that period.  That presents a very concrete manageability issue at the trial court level.

Furthermore, there aren’t clear ways to evaluate whether a single district is a partisan gerrymander.  Just because the district is flipped from one party to another shows little, as it may be part of an effort to correct a previous gerrymander.  Moreover, one district’s lines are also the lines of other districts, and so some kind of statewide analysis will be needed just to decide whether the apportionment of one district represents an excess partisan gerrymander or rather a necessary accommodation for legitimate redistricting concerns elsewhere in the State.  Because the standard for so deciding specific district cases is necessarily subjective, there is great likelihood that each judicial result will be evaluated, by both scholarly and popular commentary, as a product of the judges’ political allegiances.  This is precisely the concern that Chief Judge Roberts expressed at oral argument in our case.  Under a statewide approach, there are more objective tests of excessive partisanship, such as the efficiency gap, the mean-median difference, and comparison of the votes/seats mismatch with the votes/seats ratios of randomly drawn computer maps using non-partisan criteria.

Finally, precisely because the standard used under a district-by-district analysis is necessarily subjective, there is very likely to be a plausible appeal directly to the Supreme Court in almost every case.  The Court has already experienced this in the racial gerrymandering cases. The Court can avoid hearing these cases only by summarily affirming the trial court (or in a few cases by summarily reversing).  But because these cases bring with them intense political interest, and often significant consequences, summary disposition will often be difficult.  This is not good for the Supreme Court’s workload.  It may present a real manageability issue at the Supreme Court level.