DPS officers set up spike strips, designed to puncture a fleeing suspect’s car during a high-speed chase, along Leija's route. Mullenix set his up near an overpass further down the interstate. He then radioed one of the pursuing officers and proposed trying to shoot Leija’s car to disable it, which he had not been trained to do. The other officer told him to “stand by” and “wait to see if the spike strips work.” Leija’s family claims Mullenix heard this response; Mullenix denies it. Mullenix then took out his service rifle, waited on the overpass for Leija to arrive a few minutes later, and fired six shots at the vehicle as it passed under him toward the spike strips. Four of the shots struck Leija, killing him.

Leija’s family subsequently sued Mullenix, arguing the officer’s excessive use of force violated Leija’s Fourth Amendment rights. Lower courts agreed and waived Mullenix’s qualified immunity, which protects police officers from legal liability unless they violate clearly established constitutional rights. But in an 8-1 decision, the Supreme Court ruled Mullenix was indeed protected by it in this case because the inappropriateness of his actions had not been sufficiently established under existing precedents.

The Court decided the case per curiam, meaning “from the bench,” with no oral arguments and no individual name attached to the opinion. Only Sotomayor dissented from the Court’s consensus, though Justice Antonin Scalia filed a brief, separate concurrence in which he distinguished between the “use of

force that happens to kill the arrestee” and the “application of deadly force.”

First, Sotomayor wrote that Mullenix failed to prove shooting Leija was necessary when the spike strikes would have stopped his car and ended the pursuit without lethal force. Accordingly, she then alleges the majority “glossed over the facts” of the case and wrongly focused on the decision to stop the car instead of the manner in which Mullenix did it. Finally, she notes Mullenix’s first words to his superior officer after killing Leija were, “How’s that for being more proactive?” He was apparently referencing another officer’s critique during a counseling session; Sotomayor said the remark reflected “the culture this Court’s decision supports” when it shields an officer who used deadly force “for no discernable gain and over a supervisor’s express order to ‘stand by.’”

Sotomayor’s concerns about the Fourth Amendment long precede this case. One of the earliest and most significant examples came in the 2012 case United States v. Jones. In that case, federal agents clandestinely attached a GPS tracking device to the car of Antoine Jones, a Washington, D.C., nightclub owner, without a valid warrant and monitored his movements for a month. Federal prosecutors then used the information obtained from their surveillance to convict Jones of narcotics trafficking, for which he received a life sentence. Jones challenged his conviction by arguing the warrantless monitoring of his movements violated the Fourth Amendment.