The U.S. Supreme Court in recent years has been deciding fewer cases on the merits than it has at any time since the end of the U.S. Civil War.

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Yet, the volume of cases eligible for its review in the U.S. Circuit Courts of Appeal, and in state supreme courts, is at a near record high. Likewise, the number of certiorari petitions filed is near record highs.

Also, with thirteen different U.S. Circuit Courts of Appeal, the highest military court, 50 state supreme courts, and the highest local courts of the District of Columbia, Puerto Rico, and a handful of U.S. territories all making decisions independently, and federal law having a much more pervasive influence on civil and criminal matters in the U.S. than in most of the post-Civil War era, the potential for conflicts in interpretations of federal law between the almost 70 highest courts it supervises has never been greater. (The U.S. Supreme Court also has a small original jurisdiction docket, mostly consisting of disputes between U.S. states over water rights, consisting of about 5 cases a year.)

And, the U.S. Supreme Court has more justices, now nine, than it did when it was first formed, and much more staff to deal with those cases and to assist the justices in writing opinions on the merits in the cases before it.

The smaller number of cases from 1792 to 1850 is easy to understand. There were fewer people bringing fewer lawsuits and being prosecuted for fewer federal crimes, there were fewer state supreme courts, and there were fewer U.S. District Courts, and the federal governments regulatory scope and the scope of its activities relative to state governments and the state courts in that time frame was much smaller. (The U.S. federal government's scope and professionalism expanded dramatically during the U.S. Civil War and again during the New Deal and World War II.)

The drop in the first peak, in the 1890s, is also easily understandable. This is when the U.S. Courts of Appeal were created. Before then, in addition to reviewing final decisions on matters of federal law from state supreme courts, the U.S. Supreme Court was also the only court with appellate jurisdiction over the U.S. District Courts.

But the subsequent peaks and declines in U.S. Supreme Court caseloads are harder to explain.

Why has the number of U.S. Supreme Court decisions declined so steadily in the 20th century and 21st century?

One paper looking at the period from the early 1980s and early 1990s suggested that more cases are taken up when there is ideological homogeneity on the court (which makes some logical sense because four out of nine justices must agree to take up a case on the merits), but this is insufficient to explain the longer term trend, and is disputable and somewhat vague.

A previous answer to a similar question at Politics.SE looking at the 1984-1994 also suggested that it could be related to Congress enacting fewer laws and there is some correlation there. But a large share of the work of the U.S. Supreme Court does not involve statutory interpretation, and a small number of mostly old statutes (e.g. 42 U.S.C. § 1983) dominant the ranks of statutes that are litigated and few of those were recently amended, so the line of causation from rates of Congressional statutes enactments to U.S. Supreme Court merits decisions is not obvious.

  • To make it clearer, exactly which time period do you think warrants consideration? 1900 to present day, I take it? Because if you're interested in more than 4 years ago it might help us avoid a devolution into certain current political issues. Also, your graph is labelled as "signed decisions per term", which doesn't seem related to "cases reviewed on the merits per term", though perhaps I'm just misinterpreting... Sep 2, 2020 at 18:00
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    @zibadawatimmy Only cases reviewed on the merits generate opinions. The number of signed decisions per year isn't exactly the number of cases decided on the merits, as there can be per curiam decisions (a tiny percentage of the merits decisions) and there can be more than one opinion in a case, but the ratio of majority to concurring and dissenting opinions has, if anything gone up and not down, so it is a good proxy. I'm interested in since 1900, but I do think that political issues are plausible possible explanations.
    – ohwilleke
    Sep 2, 2020 at 18:03
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  • @RickSmith Not an exact duplicate, but interesting and relevant.
    – ohwilleke
    Sep 2, 2020 at 19:21

2 Answers 2


It's difficult to provide a substantive answer to this, as the Court basically never explains why it takes or refuses any given case. But we can observe an obvious correlation.

Before 1990, your graph shows an upward trend, but it suddenly falls by a lot over the next couple of years, and then starts trending downward. This coincides almost precisely with the retirements of Justices Brennan, Marshall, White, and Blackmun (in that order) from 1990 to 1994, and their replacement with Justices Souter, Thomas, Ginsburg, and Breyer (respectively). Correlation is not causation, but the timing is simply too good for me to ignore this.

In general, the Court decides which cases to take by voting. If at least four justices want to take a case, then it is accepted. So making such a large change in the composition of the court over such a short period of time would certainly have a significant effect on voting patterns, and it's not too surprising to me that the Court abruptly changed how many cases it was accepting.

Of course, what you really want to know is why the new justices voted to accept so few cases. But we can't read minds. The best we can do is speculate that it might have been one or more of the following:

  • Increasing political polarization.
  • Increased concern about public perception of the court (which might have reduced the number of dissents as well as the number of cases accepted).
  • A difference in attitude between the old and new justices.
  • The lack of ideological homogeneity, as you suggest.
  • Some other internal or external factor.

Until one of those four justices (Souter, Thomas, Ginsburg, Breyer) writes a memoir about their early years at the Court, I'm afraid we just won't know why things changed so dramatically over that period. Souter is retired, but he actually still sits by designation on the First Circuit Court of Appeals from time to time, so I doubt he's going to do that any time soon.


"Before 1990, your graph shows an upward trend, but it suddenly falls by a lot over the next couple of years, and then starts trending downward. This coincides almost precisely with the retirements of Justices Brennan, Marshall, White, and Blackmun (in that order) from 1990 to 1994"

should be ->

"Before 1982, your graph shows an upward trend, but it suddenly falls by a lot over the next twelve years, and then starts trending downward. This coincides almost not at all with the retirements of Justices Brennan, Marshall, White, and Blackmun (in that order) from 1990 to 1994"

the trend before and after these years does not differ significantly

Why do you think that ideological polarization is an insufficient explanation? Ideological polarization is a long-term and gradual trend, culturally even if not in the specific composition of the justices.

The decline seems to start around the first "modern" and controversial Supreme Court appointment hearing of Robert Bork and the 1994 elections and Newt Gingrich era was the result of a trend toward increasing polarization, following the ending of the post-war liberal consensus.

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