The case is Brisco v. Ercole, decided on May 13. The criminal defendant was convicted of burglary and petit larceny. An elderly neighbor complained that someone had invaded her house and that he ran away. He was wearing maroon shorts. The police canvassed the neighborhood and found Brisco, who claimed to renovating his sister's house. The police asked Brisco if he would stand in front of the victim's house next to the officers and in front of the police cars. He also agreed to place his maroon shorts over his pants so the victim could determine if Brisco looked like the burglar. "That's him," she said, between 15 and 50 feet away, looking at Brisco from inside the house. Brisco was convicted and then challenged that conviction in federal court under the habeas corpus statute.
The federal trial court determined that the police "line up," such as it was, was unconstitutional because it was too suggestive. After all, Brisco was standing next to police officers and their vehicles when the victim identified him. In particular, according to the Court of Appeals, the trial judge decided that "the circumstances of the nascent police investigation did not create a need or exigency to justify a showup, as opposed to a lineup or some other means of identification, and (2) the circumstances of the showup itself were 'highly' and 'impermissibly suggestive.'”
The Second Circuit reverses the habeas grant, and Brisco is again a guilty man. The state court conviction did not unreasonably apply clear Supreme Court authority. While it's true that "show up" identifications involving one suspect have been “widely condemned, a claimed violation of due process in the conduct of a confrontation depends on the totality of the circumstances surrounding it." Stovall v. Denno, 388 U.S. 293, 302 (1967). For the show-up identification to be illegal, it has to be "unnecessarily" suggestive.
So here is the legal standard in a nutshell:
Even if an identification procedure is unduly suggestive, the out-of-court identification may nonetheless be admissible if other factors indicate that the identification is independently reliable. To ascertain whether an identification “has reliability independent of the unduly suggestive identification procedures,” courts generally look to five established factors, first set forth in Neil v. Biggers, 409 U.S. 188 (1972):
 the opportunity of the witness to view the criminal at the time of the crime,  the witness’ degree of attention,  the accuracy of the witness’ prior description of the criminal,  the level of certainty demonstrated by the witness at the confrontation, and  the length of time between the crime and the confrontation.
The state court that convicted Brisco did not unreasonably apply Supreme Court precedent. Under the legal standard governing show-up identifications, trial courts have significant leeway in exercising judgment on these issues. Among other things, the Second Circuit noted, the New York Court of Appeals (which heard Brisco's appeal in the state system) "concluded that the [identification] procedure[ ] used w[as] reasonable under the circumstances” because it “took place at the scene of the crime, within an hour of the commission of the crime, and in the context of a continuous, ongoing investigation. The circumstances of the ongoing investigation, in the court’s view, made the procedure reasonable. Second, the [state] Court of Appeals concluded that the identification procedure was not 'unduly suggestive,' because Kemper, the eyewitness, 'initially and independently identified [Brisco,] relying on his height, hair color, and build.'”
The fact-intensive nature of these inquiries gives state courts the benefit of the doubt on the legality of show-up identifications. So even if the identification was in fact illegal under the U.S. Constitution, the defendant loses the habeas petition because the state court did not unreasonably apply Supreme Court precedent.