Justice Clarence Thomas’s voice sounded in the Supreme Court chamber on Thursday, as he read aloud short summaries of two majority opinions he authored. But he spoke loudest in a third case, without saying a word.  

In McFadden v. United States, Thomas wrote for a nearly unanimous Court rejecting the government’s argument that it could prosecute sellers of “analogue drugs”—that is, new “designer drugs” that mimic the effects of drugs banned by the Controlled Substances Act—without proving that the seller knew the new drug was functionally the same as a “controlled substance.”

He drew a laugh when he noted that the drugs McFadden had sold were labeled “bath salts.”  That part of the opinion, he ad-libbed, was “a sentence which I do not fully understand.”

In the second opinion, he wrote for a near-unanimous Court that an Arizona town could not enforce a complex sign regulation that treated temporary church “directional signs” less favorably than political, ideological, or real-estate related signs. The Sign Code, Thomas wrote in Reed v. Town of Gilbert, “is content based on its face,” because signs are regulated differently because of the particular messages they convey.  It was a fairly orthodox application of the Court’s emerging First Amendment jurisprudence. “Content-basis,” for a government regulation of speech, is almost always the harbinger of impeding doom.

But it was in a third case, Walker v. Texas Division, Sons of Confederate Veterans, Inc., that Thomas made his voice heard most clearly—by his silence. In Walker, Thomas defected from the very First Amendment orthodoxy he defended in Reed. Remarkably enough, he joined the Court’s four moderate-liberals—Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor, and Elena Kagan—to provide a decisive vote to allow the state of Texas to refuse to print a specialty license plate bearing the much-loved and hated Confederate battle flag. In an opinion by Breyer, the 5-4 majority held that a government can, with few limits, decide to convey any license-plate message it wants, and bar any that it disapproves. This isn’t “content-based” regulation of speech; the plate is speech by the government itself, and the First Amendment does not apply.

In Walker, Justice Samuel Alito wrote a dissent that could have come from Thomas’s pen. Alito argued that Texas’s rejection of the battle flag was “blatant viewpoint discrimination”—which is, in First Amendment doctrine, worse than the Sign Code in Gilbert.  

Thomas goes his own way in most areas of the law he cares about—particularly in constitutional issues. He does not mind bucking even his closest allies—witness the sedate but impassioned brawl between Thomas and Justice Antonin Scalia found in their dueling opinions in Zivotofsky v. Kerry, the Jerusalem-passport case decided last week. Scalia, in dissent, thought it plain that Congress could require the president to stamp “Israel” on passports as the birthplace of American citizens born in Jerusalem; Thomas, concurring with the majority but writing only for himself, argued that the statute violated the president’s “residual foreign affairs powers” (whatever they are) but that Congress could require the president to stamp Jerusalem on the same person’s “Consular Record of Birth Abroad.” It was an opinion that pleased neither side entirely, and puzzled many quite a bit.

Why would Thomas cross over in the Sons of Confederate Veterans case? To state the obvious, Thomas is the Court’s only African American. Much has been made of his rejection of contemporary civil-rights orthodoxy. But it is equally clear that Thomas retains vivid and bitter memories of his poverty-stricken childhood in the Jim Crow South—and that he retains a particular hatred for the symbols of Southern white supremacy.

Thomas’s most powerful moment on the bench occurred in a case concerning a similar symbol—the burning cross. The year was 2002; Virginia v. Black was a challenge to a Virginia criminal statute that forbade burning a cross with the intent to intimidate another person. A decade before, the Court had struck down a local ordinance in St. Paul, Minnesota, that made it a crime to use symbols to arouse “anger, alarm or resentment in others on the basis of race, color, creed, religion or gender.” Scalia’s angry majority opinion broadly rejected “hate speech” regulation as “viewpoint based,” arguing that, “St. Paul has no such authority to license one side of a debate to fight freestyle, while requiring the other to follow Marquis of Queensbury Rules.”

The Virginia statute had seemed to be on its way to a similar fate. The state, and the federal government, were defending the cross ban as a regulation of “true threats,” which the First Amendment does not protect. But Thomas interrupted this line of argument to ask,  “[A]ren’t you understating the—the effects of—of the burning cross? … [W]e had almost 100 years of lynching and activity in the South by the Knights of Camellia and—and the Ku Klux Klan, and this was a reign of terror and the cross was a symbol of that reign of terror.  Was—isn't that significantly greater than intimidation or a threat?”

Even on the audio, the impact of this comment is vivid. Rodney A. Smolla, who was representing the cross burners, remembered in a recent email:

I have never seen the atmosphere in a courtroom change so quickly.  Justice Breyer, who sat next to Justice Thomas, put his arm on him, as if to say “I feel your pain.” Justice Scalia was staring at Thomas with extraordinary intensity—the sense of empathy and support was virtually palpable. Justice Scalia’s eyes left his friend Justice Thomas and he looked down and scowled at me, as I was only minutes from getting up to make my argument, and I immediately knew, from his look, that his views on the entire case had just pivoted, and that he was about to come after me—which proved entirely prescient.

Instead of striking the statute, the Court majority only narrowed it slightly. The state had to prove intent to threaten, it held, rather than assuming it from the fact of the burning cross. Thomas dissented even from that. “In every culture, certain things acquire meaning well beyond what outsiders can comprehend. That goes for both the sacred and the profane. I believe that cross burning is the paradigmatic example of the latter,” he wrote. Cross burning, he argued, is not “expressive activity”; it is “a signal of impending terror and lawlessness.”

Thomas changed the law by speaking up that day against the fiery cross. On Monday, he said nothing about the decision he joined. Breyer’s opinion, couched in the dry doctrinal language of “government speech,” said nothing at all about the history or meaning of the Confederate battle flag.

But that history is there on the page, as silent, and powerful, as Thomas’s voice Monday.