Justice Thomas writes the unsurprising opinion:
In contrast to state-sponsored courtroom practices, the effect on a defendant’s fair-trial rights of the spectator conduct to which Musladin objects is an open question in our jurisprudence. This Court has never addressed a claim that such private-actor courtroom conduct was so inherently prejudicial that it deprived a defendant of a fair trial. And although the Court articulated the test for inherent prejudice that applies to state conduct in Williams and Flynn, we have never applied that test to spectators’ conduct. Indeed, part of the legal test of Williams and Flynn—asking whether the practices furthered an essential state interest—suggests that those cases apply only to state-sponsored practices....There are no dissenting opinions, but there are three concurrences, from Stevens, Kennedy, and Souter. From Souter's opinion:
Given the lack of holdings from this Court regarding the potentially prejudicial effect of spectators’ courtroom conduct of the kind involved here, it cannot be said that the state court “unreasonabl[y] appli[ed] clearly established Federal law.” §2254(d)(1). No holding of this Court required the California Court of Appeal to apply the test of Williams and Flynn to the spectators’ conduct here. Therefore, the state court’s decision was not contrary to or an unreasonable application of clearly established federal law.
[O]ne could not seriously deny that allowing spectators at a criminal trial to wear visible buttons with the victim’s photo can raise a risk of improper considerations. The display is no part of the evidence going to guilt or innocence, and the buttons are at once an appeal for sympathy for the victim (and perhaps for those who wear the buttons) and a call for some response from those who see them. On the jurors’ part, that expected response could well seem to be a verdict of guilty, and a sympathetic urge to assuage the grief or rage of survivors with a conviction would be the paradigm of improper consideration.Does this mean the case might have been better litigated? The First Amendment argument could have been developed. (Justice Stevens makes a point of saying that argument is obviously meritless.) And there could have been more concrete information about what these buttons were like. Justice Thomas had something to say about that too:
The only debatable question is whether the risk in a given case reaches the “unacceptable” level. While there is a fair argument that any level of risk from wearing buttons in a courtroom is unacceptable, two considerations keep me from concluding that the state court acted unreasonably in failing to see the issue this way and reverse the conviction. First, of the several courts that have considered the influence of spectators’ buttons, the majority have left convictions standing. See, e.g., State v. Speed, 265 Kan. 26, 47–48, 961 P. 2d 13, 29–30 (1998); State v. Braxton, 344 N. C. 702, 709–710, 477 S. E. 2d 172, 176–177 (1996); State v. Lord, 128 Wash. App. 216, 219–223, 114 P. 3d 1241, 1243–1245 (2005); Nguyen v. State, 977 S. W. 2d 450, 457 (Tex. App. 1998). I am wary of assuming that every trial and reviewing judge in those cases was unreasonable as well as mistaken in failing to embrace a no-risk standard, and so I would find it hard to say the state judges were unreasonable in this case, given the lack of detail about the buttons’ display. Second, an interest in protected expression on the part of the spectators wearing mourners’ buttons has been raised, but not given focus or careful attention in this or any other case that has come to our notice. Although I do not find such a First Amendment interest intuitively strong here, in the absence of developed argument it would be preferable not to decide whether protection of speech could require acceptance of some risk raised by spectators’ buttons.
The record contains little concrete information about the buttons. The buttons were apparently two to four inches in diameter and displayed only a photograph of [the victim] Studer. It is not clear how many family members wore the buttons or how many days of the trial they wore them.But perhaps the buttons were small and rarely worn, in which case, it wasn't a bad decision to leave out the details.