This volume is motivated by three concerns. First is the belief that the issue of political gerrymander will play a significant (although far from dominant) role in redistricting litigation in the 1990s and thereafter. In the 1980s, the legislative and/or congressional redistricting plans of all but a handful of states were subject to lawsuits (Grofman, 1985a). Many of these lawsuits involved the issue of racial vote dilution (Grofman, Migalski, and Noviello, 1985). In the 1980s hundreds of local jurisdictions that used at-large or multimember district elections had their electoral system challenged OCo and most of the jurisdictions under challenge were forced to change their system to a single-member district plan that was not dilutive of minority voting strength (see, e.g., Brischetto and Grofman, 1988). Although partisan gerrymandering is less prevalent than racial vote dilution, in the 1990s we can expect to see challenges to partisan gerrymandering like those in the 1980s to racial vote dilution. In particular, numerous local jurisdictions that use partisan multimember district or at-large elections may be subject to challenge. Second, in commissioning essays I sought to involve a number of the leading scholars in the field so as to put together a largely selfcontained compendium of the major points of view on how issues of partisan gerrymandering are to be litigated. While the ultimate issues in constitutional interpretation are ones that the Supreme Court must resolve, and these will be resolved only after an extensive series of case-by-case adjudications-just as the actual numerical features of the one person, one vote standard evolved only in the decade of litigation after Baker v. Carr (Grofman, 1989a) OCo there is an important role for social scientists to play. Social science testimony proved important in the area of racial vote dilution by aiding courts to interpret the provisions of the Voting Rights Acts (e.g., in defining the operational meaning of terms like racially polarized voting; Grofman, Migalski, and Noviello, 1985; Grofman, 1989b). In like manner, I believe that research by social scientists will aid attorneys and the federal courts in specifying manageable standards to define and measure the effects of partisan gerrymandering. I hope this volume will prove instrumental as the beginning of such a dialogue. The third concern that motivated this volume is my view that egregious partisan gerrymandering is a violation of the Fourteenth Amendment rights of political groups, and that it is both appropriate and necessary for courts to intervene when such rights are significantly impaired. However, I recognize that the courts must steer a careful line so as to avoid encouraging frivolous lawsuits, while at the same time sending a clear message to potential gerrymanders that intentional egregious political gerrymanders, which eliminate competition and are built to be resistant to electoral tides, will be struck down. Court intervention to end egregious partisan gerrymandering is necessary for a number of reasons."