Superficially, the question in Gill v. Whitford—the blockbuster case about partisan gerrymandering in Wisconsin, to be heard next month by the Supreme Court—is a legal one. Is the test for gerrymandering adoptedby the trial court “discernible,” or rooted in the high court’s precedent, and “manageable,” or consistent in the results it would produce? Lurking beneath this question, though, is a more fundamental debate about the nature of voting and representation in modern American politics. The position the Supreme Court takes in this debate will likely influence its decision more than any legal argument.

In its amicus brief, the Wisconsin legislature tells a rosy tale of voter and legislator behavior. Wisconsin voters do not “blindly support one party or the other,” the brief contends. Rather, they often split their tickets, or change their allegiances from one election to the next, based on “issues that matter to the electorate” and “the quality of the candidates and their campaigns.” Legislators, similarly, are highly responsive to their constituents’ preferences. Competitive races “force the winning candidate to adopt more moderate, centrist positions,” while “a landslide may allow that candidate to move further from the center.”

This is indeed how American politics worked in the not-too-distant past. Between the 1964 and 1972 presidential elections, for example, there was an almost 50-point net swing in Republicans’ favor. In this era, Congress was also full of conservative Southern Democrats and liberal Northeastern Republicans. Party was plainly a poor predictor of voters’ and legislators’ choices.

Read more at Slate