Distribution of Bayesian Ideal Point Estimates of Rehnquist Court Justices.
The nomination of Judge Samuel Alito to replace Justice Sandra Day O'Connor has dramatically changed the public debate over the nominee compared to that of either Harriet Miers or now Chief Justice John Roberts. Roberts high quality but lack of a paper trail allowed his hearings to avoid direct confrontation over his positions. Miers weak qualifications allowed judicial conservatives to dominate the debate, again avoiding a direct ideological and partisan confrontation. Judge Alito, in contrast has very high qualifications, which I think cannot seriously be questioned, plus a long and clear track record of judicial opinions which will be strongly attacked by liberals and defended by conservatives. The hearings will focus on the most extreme statements that can be found by liberals in his published opinions, a defense of his views by conservatives, and an interesting opportunity to see how this plays out with the mass public. (We visited this issue before here.) It is going to be fun. This is the judicial war that both extremes wanted to have.
But how much is it likely to matter for the alignment of the Court? Both sides will claim much but the evidence is not so much.
The key to any Court is the median voter, the decisive fifth vote for any decision. In the Rehnquist Court, that vote was O'Connor's. In the Roberts Court (with Alito replacing O'Connor) that fifth vote will be Kennedy's. But as the figure above shows, Kennedy is only slightly to the right of O'Connor. Even if we assume Alito is as conservative as Scalia, and that Roberts turns out to be to the right of Rehnquist, there remain only four votes for very conservative positions. Someone must convince Kennedy to join the four most conservative Justices. (And I continue to wait for the evidence on Robert's positions.)
This configuration raises an interesting problem for the Roberts-Alito additions to the Court. Kennedy was only slightly to O'Connor's right. But there will be a substantial gap between Kennedy and the group of Roberts-Alito-Thomas-Scalia. There will be a similarly large gap between Kennedy and the group to his left: Stevens-Bryer-Ginsburg-Souter. If Roberts and Alito turn out to be near Thomas and Scalia, Kennedy will actually be closer to the liberal wing. As such, a stronger conservative wing of the court could drive the swing vote to the left. The conservative Justices will have to make sure this doesn't happen, and in doing so will have to moderate their views enough to win Kennedy's support. The liberals will similarly have to moderate their views to win Kennedy over to their side.
Regardless of where the wings of the Court stand, Kennedy is the key vote. With O'Connor on the Court, it was possible to win a majority by gaining either Kennedy's or O'Connor's vote. The figure shows considerable overlap between their estimated locations. The liberal wing could win with either O'Connor's or Kennedy's votes, and sometimes both. The conservative wing required both Kennedy and O'Connor to win.
Now Kennedy stands alone in the middle of the Court. Neither wing can win without him. This gives him tremendous leverage to shape opinions to his satisfaction, and requires both wings to be far more deferential to his views.
The upshot is that conservatives are likely to be disappointed once more with the outcome of a new conservative appointment to the Court. Despite adding Roberts and Alito, the Court is likely to remain a center-right Court, and not a "right-right" Court. Not unless Kennedy changes his positions.
So sit back and watch the huge fight we are going to see over Alito, with claims that the fate of civilization as we know it hinges on his confirmation or defeat. But don't be shocked when the Court fails to shear sharply to the right after his confirmation.
If you want to look for the day of real change in the Court, wait for the next appointment after Alito's. And remember that President Bush had 39 months still to serve. The odds are good that he'll have at least one more appointment. If one of the liberals, or Kennedy, retires, that appointment will be the one that shifts the median in a big way.
(The ideal points presented here are my estimates based on the Justices voting on decisions during the Rehnquist Court. For much more excellent analysis of this see the work by Martin and Quinn here. Their work produce slightly different estimates, but the same qualitative conclusions.)
7 comments:
It may only shift it slightly right but isn't the real measure (and the fear of many on the left) is that it would be more likely to shift the balance of power from 4.5 vs 4.5 to 4 vs 5? Replacing O'Connor with anyone to the right of Kennedy is enough to shift this.
But this "measure of relativity" displayed in your graph raises a question for me: What is it about Supreme Court (ideal point) voting that causes those closer to the median to be more "consistent" (tighter spread on their ideal point distribution) than those to the extreme? It would have been my naive guess that those to the extremes would be tighter while those to the center would be wider (i.e., consensus builders). Shows what I know...
Rudy,
I think the median voter controls the outcome, so I see it still as a centrist court, not a 4-5 right court. Of course I believe in both the median voter theory AND the tooth fairy, so others may differ.
On the precision of estimates-- imagine two justices: one votes 50-50 between the right and left. The other 100% right (or left). The 50-50 judge is pretty clearly at the dead center. The 100% right judge is... how far to the right? We have literally not seen a case that is too far right for him to support. So perfect extemist voting actually leaves us more uncertain as to the ideal point of the extreme judges, while the consistent mid-point voting mix gives pretty precise information about moderates. Hence a little tighter estimates towards the middle and a bit more variance for the extremes.
\chf
With an electorate of only nine people, I am not sure that the median is appropriate. Personal relationships are going to play a role. For example, last week’s New Yorker had a profile on Breyer and his courting of O’Connor: “In conversation, Breyer often invokes Sandra Day O’Connor, with whom he had a close relationship… Breyer and O’Connor shared a judicial disposition—pragmatic, improvisational—that distinguished them from their more rule-based colleagues, including Scalia and Ginsburg. Breyer likes to win cases, and O’Connor, the Court’s swing vote, was a means to that end… Akhil Amar, a professor at Yale Law School, who clerked for Breyer on the federal Court of Appeals in the mid-eighties, says… ‘Nino Scalia would rather be right than in the majority, but Breyer by temperament is someone who is going to find the center. He cultivated O’Connor in the way that Scalia drove her away’” (the piece is available here). Replacing O’Connor with a noticeably more conservative justice could shift the court much farther than the model would imply. It can be hard to guess the voting patterns on the court because we just don’t understand the deliberation process or the institutions that govern the Court’s internal politics.
If you prefer small group psychology you probably think it matters a lot that Breyer is a nice guy who courts O'Connor and the Scalia probably looses decisions because he isn't warm and fuzzy.
If you prefer rational models of behavior, then you prefer to believe that O'Connor sides with Breyer when her preferences and his coincide, and that Scalia hasn't won more decisions because he insists on writting opinions that are simply too far to the right for O'Connor and Kennedy to agree with (some, but certainly not all, of the time.)
An alternative critique of my analysis is that the Court isn't really one dimensional, and in that case median voter models break down into chaos. I'd say the empirical evidence is against chaos, but why that is isn't obvious, at least to me.
Thanks for the comment-- I expect most lawyers would prefer not to believe the spatial model of the Court, prefering to believe that they can always craft a winning argument by exploiting multidimensional aspects of the case.
See http://wonktron.blogspot.com/ for an extended version of a brown's comment. The New Yorker article he/she linked is also interesting if you haven't seen it.
\chf
I guess my concern was over how much the new median voter (Kennedy) might shift if Alito replaces O'Connor, since Ideal Point scores are relative measures of space between each individual.
So I took the quick example that Martin and Quinn make available in MCMCpack (43 non-unanimous votes in the 2000 court) and generated the following density plots (forgive the rush job on this - no purty colors and labels):
O'Connor Court
Pretty similar to what you have.
Okay, assuming that on the new court, Roberts votes exactly like Rehnquist (he was his intern afterall), I made Rehnquist into Roberts and I removed OConnor from the data and replaced her with Alito. I just made Alito's votes the majority position of Thomas, Rehnquist/Roberts, and Scalia. This generates the following ideal point densities:
Alito Court
Not that much of a difference with respect to the position of the median voter if this is how things were to turn out.
But what it does show in comparison is that there is one lone median voter on this court as opposed to the two median voters before. What pressure would this exert on Kennedy if left standing alone in the middle with no other near ideological colleague to lean on for support?
Ooooo. Cool and clever! I like it. I'm releived that the Alito experiment doesn't change things much, but that is a nice way to test the sensitivity.
If I wear my spatial modelling hat, I think I continue to believe that Kennedy is the pivot and what he wants, he can get. Such is the power of the median voter. If I take off that hat, then I can imagine a cohesive right block that can persuade Kennedy to accept some more of their arguments. And maybe Roberts has such charm that he can persuade Kennedy to shift right.
But in the end, I believe Justices have pretty strong views, and I believe in the power of the median voter!
\chf
Nice work. I am surprised so many people on the left and right alike believe this nomination will radically shift the court. The Supreme Court won't really shift to the right until one of the liberal justices dies/resigns/retires and is replaced by a conservative.
It's not rocket science, either.
But nice post, still.
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