Thread by @_MiguelHernan

This week the US Supreme Court refused to remedy an extremely serious constitutional violation.

All because a majority of the Court's Justices don’t know how to handle quantitative information.

Bad times for democracy when numerically illiterate people are in charge.

THREAD👇

Background:

Each state is divided into districts and each district sends a representative to Congress.

States decide how to draw district lines.

The state's ruling party is tempted to redistrict to maximize its % of seats in Congress. This is known as partisan gerrymandering.

Examples:

In North Carolina, Republicans received 49% of the vote, but won 9 of the state’s 13 seats in Congress in 2012.

In Maryland, Democrats never received more than 65% of the vote but won 7 of 8 seats between 2012-18.

etc.

Individual constitutional rights are violated.

The Supreme Court acknowledged that “excessively partisan redistricting is inimical to our democratic form of government and violates the U.S. Constitution” (Vieth v. Jubelirer, 541 U.S. 267, 2004)

But this week the Court ruled that it'll do nothing about it. Too bad, it said.

The Court’s argument for doing nothing goes like this:

"There is no standard to identify extreme partisan redistricting so we will let lower courts decide what to do."

This argument is doubly flawed.

1. Lower courts DO USE a standard so the Court's argument is contradictory.

2. A standard CAN be defined to determine when a redistricting plan is so biased as to render it unconstitutional.

But it must be defined quantitatively because partisan redistricting uses computational tools. The Court’s majority would abdicate its duties rather than use math.

In a dissenting opinion, Justice Kagan said: “For the first time in this Nation’s history, the majority declares that it can do nothing about an acknowledged constitutional violation because it [...] cannot find a workable legal standard to apply.”
Read it
supremecourt.gov/opinions/18pdf…

Justice Kagan and her dissenting colleagues, but apparently not Chief Justice Roberts and his majority colleagues, know how to reason numerically.

To learn how to create a standard of extreme bias, Justices just had to read @ericlander’s Amicus brief:
brennancenter.org/sites/default/…

Lander's proposal (oversimplified):

Generate thousands of redistricting plans that meet the state’s declared goals.

Place them along an axis the measures, say, the number of Republican seats.

If the State’s chosen plan is an extreme outlier, then it is excessively partisan.

We now have a metric of partisanship: percentile of the proposed redistricting plan.

Take North Carolina: Every single one of 3,000 possible redistricting plans would have elected at least 1 more Democratic seat than the state’s actual plan, and 77% would have elected 3-4 more.

That is, the consultants hired by the state’s Republicans considered thousands of possibilities and chose the most extreme outlier. (They even said so explicitly.)

So a quantitative “extreme outlier” standard can be applied to resolve claims of excessive partisan gerrymandering.

By setting a threshold for outliers, the Court could set a judicially manageable standard for unconstitutional gerrymandering.

Yet the Court declined to do so despite being presented with extreme partisan redistricting plans that were beyond the 99th percentile of possible plans

Worse, the majority didn’t even respond to Lander’s & others’ proposals.

Rather, the Roberts Supreme Court proposed to address excessively biased redistricting through the legislative process with new laws. That proposal is either disingenuous or ignorant because, as Kagan says:

Extreme partisan redistricting is a major threat to democracy. It's also quantifiable using computational methods.

The Roberts Supreme Court, however, declares itself incapable of quantifying the threat.

So sad that our nation's future is shaped by 5 innumerate Justices.

END

Correction: Eric Lander's Twitter handle is @eric_lander

Some people below argue that the Court was right in not drawing a bright line (say, at the 67th percentile) to classify districting plans as extreme/non-extreme because doing so could be arbitrary.

Like the 5 Justices, they are neglecting the available quantitative information.

Yes, one might reasonably argue that the Court didn't need to draw a bright line, just rule about 2 districting plans, of which at least one was an outlier >99th percentile.

But anyone who understands "99th percentile" will agree partisanship was extreme. Far from the grey area.

Both the quantitative arguments and their constitutional basis are explained in detail here:

@eric_lander's Amicus Curiae Brief brennancenter.org/sites/default/…

Kagan's dissenting opinion (p. 40) supremecourt.gov/opinions/18pdf…

Please quote sections from these documents if arguing otherwise.