While conventional wisdom among U.S. Supreme Court watchers is that the narrowness of many of the justices’ recent decisions has created a “faux-nanimity,” the court’s docket control — its ability to pick and choose which cases to hear — goes even further in explaining why the justices are agreeing at record rates. Last week’s denial of review in a key sentencing case — Jones v. United States, on which more anon — is just the most recent example of the court side-stepping its responsibility to grapple with issues that demand its attention.

It’s not just high-profile culture-war issues like same-sex marriage and the right to bear arms that the Supreme Court is avoiding like the plague. On issues ranging from federalism to property rights to broadcasting regulation, the court increasingly declines to hear any case it doesn’t absolutely have to — no matter how critical the questions presented — especially if there’s a threat of an irreconcilable split among the justices.

This extreme selectivity goes a long way to explaining the growing unanimity and is a reflection of the “judicial minimalism” that Chief Justice John Roberts has vowed to instill. To extend a metaphor he used during his confirmation hearings, it’s much easier to call balls and strikes when all the pitches are either right down the pipe or way outside.

Jones, a constitutional criminal procedure case, was the court’s latest big “decision not to decide.” The issue there was whether a defendant can be sentenced for conduct of which he was acquitted, based on facts that the judge determined. (Read that sentence again; I’m not making this up.)

In United States v. Booker (2005), the Supreme Court held that the Sixth Amendment prohibits a judge from sentencing a convicted defendant to a prison term exceeding the law’s maximum penalty for the crime committed unless additional aggravating facts are found by the jury or admitted by the defendant. The court also held that all sentences must be reasonable.

In a subsequent case, Justice Antonin Scalia wrote a concurrence in which he expressed concern about situations in which judges issue sentences below the statutory maximum, but which would only be reasonable in light of additional facts found solely by the judge. He proposed a doctrine in which the reviewing court asks whether the sentence would be reasonable as applied only to those facts found by the jury.

The situation that Scalia feared became manifest in Jones for three criminal defendants who were convicted of selling small quantities of drugs but acquitted of conspiracy charges relating to larger quantities. Despite the acquittals, all three received sentences four times greater than any other defendant convicted of the same crimes in the post-Booker era using the U.S. Sentencing Commission’s guidelines.

The defendants argued — and no prosecutor or judge has disputed — that their sentences would be unreasonable without consideration of the additional conspiracy evidence. The U.S. Court of Appeals for the D.C. Circuit nevertheless affirmed the sentences, declining to adopt Scalia’s proposed doctrine.

But shouldn’t the Sixth Amendment be read to prohibit increased sentencing based solely on judge-found facts, regardless of whether the final sentence remains below the statutory maximum? Indeed, the defendants’ constitutional right to a jury trial can be traced back to Article 39 of the Magna Carta — the celebrated document that will mark its 800th anniversary in June — which is also the historical origin of the Constitution’s prohibition on ex post facto, or retrospective, criminal laws.

Article 39 reflected a deep concern that the government would undermine the jury’s role and imprison defendants without the input of their peers. Given the status of sentencing guidelines as “law” for purposes of the ex post facto clause, the Sixth Amendment should extend to the defendant’s right to the “lawful judgment of his peers,” meaning that a judge can only render a sentence based on the jury’s factual findings.

In other words, if it’s unconstitutional to sentence a defendant based on rules issued after he commits the purported crime, it must be unconstitutional to sentence a defendant without the input of his peers.

Despite the seeming incongruity between the Sixth Amendment jury right and sentences based on judge-found facts — not to mention the injustice of it all — the Supreme Court declined to hear this case.

While normally we don’t know what the justices are thinking when they deny a cert petition — or even if anybody disagreed — but in the Jones denial, Scalia wrote a rare dissenting opinion, joined by Justices Clarence Thomas and Ruth Bader Ginsburg. Here’s the salient bit:

“The Sixth Amendment, together with the Fifth Amendment’s Due Process Clause, ‘requires that each element of a crime’ be either admitted by the defendant, or ‘proved to the jury beyond a reasonable doubt.’ Any fact that increases the penalty to which a defendant is exposed constitutes an element of a crime, and ‘must be found by a jury, not a judge.’ We have held that a substantively unreasonable penalty is illegal and must be set aside. It unavoidably follows that any fact necessary to prevent a sentence from being substantively unreasonable — thereby exposing the defendant to the longer sentence — is an element that must be either admitted by the defendant or found by the jury. It may not be found by a judge.”

And so the petitioners came one vote short of the four needed to grant. The three dissenters may seem like an unusual grouping, but actually these justices vote alike on criminal defendants’ jury-trial rights. They were together in Booker, for example, as well as in more recent cases involving the right to confront witnesses. It’s sort of the court’s left and right against the center.

Alas, the Scalia trio was traditionally joined in these kinds of cases by Justices John Paul Stevens and David Souter, who have since been replaced by Justices Sonia Sotomayor and Elena Kagan, respectively. It’s not a big surprise that Kagan seems to have joined the “pragmatic” bloc for these purposes, but Sotomayor’s vote is disappointing. Some commentators point to her background as a prosecutor to explain such deference, but Sotomayor is one of the most pro-defendant votes in Fourth Amendment and habeas corpus cases.

Whatever the reason for the lack of a crucial fourth vote, the Supreme Court missed an opportunity for principled jurisprudence. And while the Sixth Amendment isn’t the sexiest constitutional provision — sentencing cases often make one’s eyes glaze over — the justices’ demurral in Jones is but the latest example of how the court increasingly shirks its primordial duty to say what the law is.