Justice Clarence Thomas has long approached the law the same way that Heath Ledger’s Joker approaches urban peace. He’s suggested that federal child labor laws and the ban on whites-only lunch counters are unconstitutional, written opinions that would blow up multiple federal agencies, and argued that high school students lack First Amendment rights because 17th century self-help books told parents to be cruel to their children.

Yet, on Monday — after nearly three decades on the Supreme Court — Thomas finally articulated his approach to stare decisis, the principle that courts should generally follow the rules announced in past decisions.

And, oh boy, is Thomas’ opinion in Gamble v. United States a doozy.

Though Thomas dresses up his concurring opinion in Gamble with a few paragraphs that seem to soften his conclusion, the rule he ultimately articulates would give his court free reign to burn down any decision that five of its members do not like. It’s the kind of judicial arson one might expect from a justice who, after spending much of his career writing lone dissents that had little impact on his colleagues, now thinks he may have the votes to do things his way.

“When faced with a demonstrably erroneous precedent, my rule is simple,” Thomas writes. “We should not follow it.” That may seem like a workable rule — how bad does a decision have to be before it is “demonstrably erroneous?” — but bear in mind that this rule comes from a man who has serious doubts about child labor laws.

There are many reasons why courts typically adhere to stare decisis. Stability in the law is an important virtue, for one thing. Legislatures will pass laws, companies will make investments, and individuals will shape their actions based on their assessment of existing precedents. If those precedents can be wiped away on a whim, all of this planning will be for naught. And many crucial investments may never happen because investors cannot plan for an uncertain future.

Stare decisis also helps depoliticize the law. When the Supreme Court’s political center of gravity changes — as it has shifted to the right under President Donald Trump — it’s tempting for the new majority to declare themselves victors and start pillaging old precedents they do not like. If power shifts again, the new majority might be equally tempted to retaliate, burning their vanquished foe’s decisions to the ground. That’s not just a recipe for instability, it’s a recipe for the kind of politics that turns Supreme Court nominations into existential fights between the two major political parties. Moreover, it’s a recipe for a court that strips power from the elected branches and claims it for itself.

But, perhaps most significantly, stare decisis is about modesty. Consider, for one moment, the fact that many provisions of the Constitution live in a state of ambiguity.

What on earth are the “privileges or immunities of citizens of the United States?” What makes a search or seizure “unreasonable?” Which punishments are “cruel and unusual?” If the government wants to deny someone “liberty,” how much “process” is “due?” What is a “public use” of private property? How should the United States guarantee a “republican form of government?” What is the “general welfare of the United States?” Which laws are “necessary and proper” for carrying into effect Congress’ enumerated powers?

There is significant historical evidence, moreover, that many of these provisions were intentionally written to be ambiguous — either because the framers hoped that the courts would be able to transform vague principles into actionable rules, or because political compromises and the fear of a looming election prevented a supermajority of Congress from agreeing on clearer language.

As NYU law professor William Nelson wrote in a seminal book, “the debates on the Fourteenth Amendment were, in essence, debates about high politics and fundamental principles.” But they “did not reduce the vague, open-ended, and sometimes clashing principles used by the debaters to precise, carefully bounded legal doctrine.”

It is arrogant in the extreme, in other words, for a judge to assume that they alone have determined the one true meaning of a legal text as vague as the Constitution. The only way for the law to have any stability whatsoever is for judges to accept that the men and women who came before them typically acted in good faith to read difficult-to-interpret language. And the work of those men and women should not be idly cast aside simply because the current crop of justices think that they could do it better.

And yet, that’s more or less what Thomas says should happen in his Gamble opinion.

“By applying demonstrably erroneous precedent instead of the relevant law’s text—as the Court is particularly prone to do when expanding federal power or crafting new individual rights—the Court exercises ‘force’ and ‘will,’ two attributes the People did not give it,” Thomas writes. Instead, he would have his court, “restore our stare decisis jurisprudence to ensure that we exercise ‘mer[e] judgment,’ which can be achieved through adherence to the correct, original meaning of the laws we are charged with applying.”

Again, all of this rhetoric may seem reasonable in the abstract. But remember that it comes from a man who’s suggested that that decisions upholding a ban on whites-only lunch counters “drifted far from the original understanding of the” Constitution. Now, ask yourself if you want him to have an unchecked power to decide which decisions are “demonstrably erroneous?”

The Gamble case itself involves an unfortunate doctrine which the Supreme Court upholds as firmly grounded in precedent. The Fifth Amendment provides that no one shall “be subject for the same offense to be twice put in jeopardy of life or limb.” Yet the court’s “separate sovereigns” doctrine creates a massive hole in the Double Jeopardy Clause. Though the federal government may not prosecute someone twice for the same crime, and neither may any state, a state may prosecute someone and then the feds may do so again.

“Even in constitutional cases, a departure from precedent ‘demands special justification,'” Justice Samuel Alito writes for a majority of the Supreme Court. And that “means that something more than ‘ambiguous historical evidence’ is required before we will ‘flatly overrule a number of major decisions of this Court.’” Alito then spends the bulk of his opinion picking apart citations to very treatises and even older British judicial decisions, to show that they offer no clear basis for dismantling the separate sovereigns doctrine.

Notably, while Thomas used this case as a vehicle to rail against stare decisis, he also joined Alito’s opinion. Apparently a case involving a man unjustly punished twice for the same crime isn’t the kind of case “expanding federal power or crafting new individual rights” that gets under Thomas’ skin.

There are a few lines in Alito’s opinion that should trouble court-watchers who are hoping that the Supreme Court’s new conservative majority doesn’t share Thomas’ desire to light a whole range of precedents on fire. At one point, for example, Alito writes that “the strength of the case for adhering to [past] decisions grows in proportion to their ‘antiquity’” — suggesting that Alito may be perfectly happy to overrule newer decisions. There’s also an unconvincing passage where Alito defends the Supreme Court’s 2008 decision in District of Columbia v. Heller, which invigorated the Second Amendment based on historical evidence that is at least as ambiguous as the evidence raised in Gamble.

But Alito’s opinion is, at its heart, a statement that precedents are powerful and they shouldn’t be disregarded lightly. That’s a statement liberals should welcome from this Supreme Court — and it is very different than what Thomas says in his concurring opinion.