A Moneyball analysis of Mitch McConnell’s Supreme Court defiance

Senate Majority Leader Mitch McConnell has vowed not to consider any Supreme Court nominee that President Obama makes. My mathematical analysis shows why: by waiting, McConnell gets a 50% chance of a conservative court, and a 35% chance of an extremely conservative court, for many years to come.

This decision is even more important than it appears. Any nominee will shift U.S. policy as key decisions on abortion, campaign finance, and same-sex marriage come before the court. It’s also rational to assume that Ruth Bader Ginsburg, the very liberal 82-year old Justice, will retire in the next four years, and the next president will replace her, again shifting the makeup of the court.

As you’ll see from this analysis, it’s clear that the pronouncements about the people’s right to decide and election-year precedents are bullshit. McConnell’s decision to confirm Obama’s nominee is completely rational from a mathematical perspective, even if it might not be from a constitutional viewpoint.

Analyzing the Supreme Court

To analyze the makeup of the court, I use this chart from the New York Times.

Supreme Court scale
Source: New York Times based on data from Lee Epstein, Washington University in St. Louis, for term ending in June 2013

I rescaled this graphic for the purposes of my analysis. Here’s where the current justices and the late Justice Scalia sit, on a scale from -10.0 (pure liberal) to +10.0 (pure conservative). For the rest of this analysis, keep in mind that negative numbers represent liberals and positive numbers, conservatives.

Kagan: -10.0
Sotomayor: -9.7
Ginsburg: -9.0
Breyer: -2.5
Kennedy: +3.3
Roberts: +6.8
Scalia: +6.8
Thomas: +9.5
Alito: +10.0

In this analysis, the concept of the median justice is crucial. The median indicates where the swing vote sits — half the justices are more liberal than the median, and half are more conservative.

Before Scalia died, the median justice was Anthony Kennedy, at +3.3. It is no coincidence that his was the swing vote in so many decisions, including the decision on same-sex marriage and the Citizens United decision.

Blocking Scalia’s replacement has only a minor effect in 2016

With Scalia gone, the Court is deadlocked. There is no median justice. The median is at 0.4, halfway between Justice Kennedy, at +3.3, and Justice Breyer, at -2.5. There will be many decisions with four justices on each side. In these cases, the court sets no precedent, and lower court decision stands. (Many of these lower courts include Obama nominees who have made more liberal decisions, so some have suggested this vacancy would give liberals an advantage.)

Suppose Obama nominates a candidate for Scalia’s replacement that the Senate could conceivably confirm — let’s say the person had a rating of -2.0 on my scale, not quite as liberal as Justice Breyer. The new justice would immediate become the swing vote, and the court would have a liberal majority.

So in 2016, the Senate Republicans’ choice is between approving this moderate/liberal nominee and living with a court whose swing vote is slightly liberal, versus rejecting or refusing to consider that nominee, and living with a deadlocked court with no swing vote, and sometimes liberal lower court opinions. This makes a difference, but does it make enough of a difference that Republicans would refuse to consider any nominees? Probably not.

But things look very different when you look beyond this year

Blocking Obama’s nominee pays off big in 2017 and beyond

To understand what will happen next year, I make the assumptions below. (Don’t get hung up on the likelihoods — the outcomes I model are not highly sensitive to changes in these percentages.)

  • There is a 50% chance that a Democrat will win the presidency.
  • There is a 40%  chance that Democrats will take over the Senate Majority. (Of 12 competitive races, 10 seats are currently held by Republicans.)
  • These two results are correlated — if a Democrat wins the presidency, the Democrats are more likely to take over the Senate, as well.
  • Ruth Bader Ginsburg, who sits at a very liberal -9.0 on my scale, is 82 years old and will likely retire in the next four years.

So, here are the four possible outcomes of the 2017 election and the results, depending on whether the Senate had earlier approved or rejected Obama’s nominee. You can see my analysis on Google Sheets if you’re interested.

  • Democrat President, Democrat Senate Majority (25% chance). President Hillary Clinton or Bernie Sanders would nominate a liberal justice (-9.0 rating) to replace Justice Ginsburg, and another, similarly liberal justice to replace Scalia, if needed. If the 2016 Senate had blocked Obama’s nominee, this would generate a court with a 5-4 liberal majority and Stephen Breyer, at -2.5, as the swing vote. The result is similar if the 2016 Senate had confirmsed Obama’s nominee: a 5-4 liberal majority, and a slightly liberal swing vote.
  • Democrat President, Republican Senate Majority (25% chance). The new president would need to nominate a moderate justice to replace the very liberal Justice Ginsburg, as well as a replacement for Scalia, if needed, in a similar power situation to the current one. Result: a 5-4 liberal majority with a moderate-voting (-2.0) liberal as the swing vote. Note that this outcome does not depend on whether the 2016 Senate confirmed or rejects Obama’s nominee, because in 2017, the new Democratic president would have to nominate the same sort of moderate nominee that Obama picked.
  • Republican President, Democrat Senate Majority (15% chance). President Rubio, Cruz, Trump, or Kasich would have to nominate a moderately conservative justice (2.0 on my scale) for both Ginsburg’s seat and, if needed, Scalia’s replacement. If the 2016 Senate Republicans had confirmed Obama’s nominee, this would generate a 5-4 conservative majority with the new justice as the swing vote, at 2.0. On the other hand, if the 2016 Senate had rejected Obama’s nominee, this generates a 6-3 conservative majority, but still with a swing vote at 2.0 on my scale. (For an unlikely but entertaining wild-card scenario in which the Democrats approve the nominee before the new president takes office, see this.)
  • Republican President, Republican Senate Majority (35% chance). In this case, the Republican President would nominate a Justice similar to Scalia or Thomas to replace Ginsburg, and another to fill the year-long vacancy, if needed. If the 2016 Senate has approved Obama’s nominee, this would generate a 5-4 conservative majority with Anthony Kennedy (3.3) as the swing vote — essentially replicating the court we have now. But if McConnell’s senate had successfully blocked Obama’s nominee, the conservatives would get their triumph: a 6-3 conservative majority on a highly conservative court with Chief Justice John Roberts (6.8) as the swing vote.

Now you can clearly see the Republican’s calculus for blocking Obama’s nominee. I looked at the weighted average of these four cases, depending on whether the 2016 Senate blocks or approves the new nominee.

If the Senate Republicans of 2016 approve Obama’s nominee, they end up with a 50/50 chance of a conservative majority on the court, with at best a moderately conservative swing vote. The majority on the court depends, basically, on who the new president is. And there’s a 50% chance the swing vote becomes moderately liberal.

On the other hand, if the Senate Republicans block Obama’s nominee, they still end up with a 50/50 chance of, not just a conservative majority, but a 6-3 majority on the court (again, determined by the new president). The weighted average of the swing voting justice is a highly conservative 5.3. They have a 35% chance of getting G.W. Bush appointee John Roberts as the swing vote. And their worst case scenario (25% chance) is a court packed with four extreme liberals, but a swing vote of the moderate Stephen Breyer.

There’s certainly a possible electoral cost to McConnell’s maneuver. But as this analysis shows, he’s got an awful lot to gain by it, and not much to lose.

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  1. Love Moneyball-style analysis but I think you may not have factored in the impact of 24-news coverage of Supreme Court confirmation hearings on voters. I’m guessing that yet another GOP-orchestrated stalemate in Washington will push voters towards Sanders or Hillary.

  2. I gotta agree with Katie.

    How’s this for a scenario for the early innings of the nomination process? If Obama nominates an excellent black woman and McConnell and Co. block the nomination. Then Obama fields an excellent hispanic nominee and McConnell blocks that one . How many nominations of qualified minorities will McConnell intentionally walk until the bases are loaded and the minority voter turnout in November is really high? High turnouts are the most likely predictor of Republican loses up and down the ticket. They could lose the Senate and the Presidency.

  3. the 2016 GOP SCOTUS blockade never came up during the election with Trump dominating the airwaves 24/7.The DNC calculus that voters would punish the GOP was a huge mistake, bordering on hubris.