Three things to watch at Supreme Court’s partisan mapmaking arguments

The Supreme Court is having another go at a question it's never been able to answer: Can partisanship ever become unconstitutionally excessive in the process of drawing legislative districts?

A year ago, the court sidestepped the question on procedural grounds in one case challenging Wisconsin's Republican-drawn state legislative map and another contesting the way Democrats drew the congressional districts in Maryland.

For two hours starting at 10 a.m. Tuesday, the court will revisit the current Maryland map, which has contributed to the election of seven Democrats but just one Republican in the last four cycles (that case is called Lamone v. Benisek) but a different challenge to a Republican effort at partisan gerrymandering. That one, Rucho v. Common Cause, centers on a House map for North Carolina that's routinely elected 10 Republicans but only three Democrats.

The cases present the justices with a clear opportunity for a landmark ruling (probably in June) about the nature of American politics, settling a dispute that has been vexing advocates for democracy reform for more than two decades: Can there ever be a constitutional limit to partisan dominance of the legislative mapmaking process? And, if the answer is yes, then what is the formula for deciding that limit?

Transcripts will be released later Tuesday, and an audio tape by the end of the week. Here are three ways to parse the arguments for clues about the outcome:

1. Will the newest justice tip his hand?

In a partisan gerrymandering challenge to Pennsylvania's map in 2004, the court ruled 5-4 against intervening, with Justice Anthony Kennedy siding with his four conservative colleagues in the majority.

Kennedy, however, opened the door to revisiting the constitutionality of partisan gerrymandering in a future case, assuming anyone could present a "manageable standard" in which to identify it.

"If courts refuse to entertain any claims of partisan gerrymandering, the temptation to use partisan favoritism in districting in an unconstitutional manner will grow," he wrote. "On the other hand, these new technologies may produce new methods of analysis that make more evident the precise nature of the burdens gerrymanders impose on the representational rights of voters and parties."

Kennedy's concern about the potential threat to democracy posed by partisan gerrymandering was clear.

But it's unclear where Kennedy's successor, Justice Brett Kavanaugh, lands on the question of the court's role in refereeing congressional mapmaking, which the Constitution has designated to the will of each state.

Kavanaugh's "balls and strikes" jurisprudence would suggest he'll be less receptive to judicial interference, but this will be his first opportunity to weigh in on the practice of partisan gerrymandering.

2. Were N.C. Republicans too transparent?

If the justices conclude gerrymandering can get too partisan for the Constitution, they won't need data analysis to identify it in one case.

State Rep. David Lewis, a leader of the GOP cartographers in charge when the current North Carolina districts were set in 2016, flat out asserted that his side's motive was to minimize Democratic power.

"We want to make clear that we, to the extent that we are going to use political data in drawing this map, it is to gain partisan advantage," he said at one legislative hearing. "I proposed that we draw the maps to give a partisan advantage to 10 Republicans and 3 Democrats because I do not believe it's possible to draw a map with 11 Republicans and 2 Democrats."

Will the judges focus on this acknowledgment in their questioning?

3. Has the chief justice's thinking evolved?

Last term, those challenging the state House map in Wisconsin offered a mathematical formula to support their case. The metric was known as the "efficiency gap," which political scientists developed to measure the number of votes "wasted" by district boundaries drawn to favor one political party.

Chief Justice John Roberts was skeptical. During oral arguments, he famously referred to the political science community's best shot at an analytical analysis of extreme partisan gerrymandering as "sociological gobbledygook."

The challenges to the North Carolina and Maryland districts will again rely on research methods developed to analytically define extreme gerrymandering. Will Roberts be as dismissive?