Javier Ambler was driving near Austin, Texas, in the early morning hours when a sheriff’s deputy tried to pull him over for failing to dim his lights. Ambler failed to stop and led police on a 20-minute, high-speed chase, which ended when he crashed into some trees. Police tased Ambler as he was stepping out of his car, and he fell to the ground. Although some of the incident was captured on dash- and body-mounted cameras, exactly what happened next is disputed. Officer Nissen, who arrived about 30 seconds after Ambler was first tased, pressed his knee into Ambler’s shoulder and his hand onto Ambler’s neck and head while other officers again tased Ambler—who at this time was warning them that he couldn’t breathe and that he suffered from congestive heart failure. Ambler then went limp and died from cardiac arrest.

In response to a §1983 lawsuit by Ambler’s family members, Officer Nissen asserted qualified immunity at the summary judgment stage, arguing that there were no material facts in dispute and that existing case law did not clearly establish that he used excessive force in helping subdue Ambler. The district court disagreed and denied qualified immunity because the summary judgment evidence did not resolve certain key facts, including how much pressure Officer Nissen exerted on Ambler’s head and neck and whether Nissen should have realized that Ambler was struggling to breathe rather than resist arrest.

Nissen appealed, and a divided panel of the Fifth Circuit agreed that material facts still in dispute deprived the court of appellate jurisdiction over Nissen’s interlocutory appeal of the denial of qualified immunity. Nissen then filed a petition for en banc review.

Cato filed an amicus brief opposing Nissen’s en banc petition. Agreeing with Nissen’s law-enforcement amici that qualified immunity case law in the Fifth Circuit has become a “morass of unpredictability,” Cato argued that granting en banc review would only worsen that morass due to the impossibility of formulating a clear rule when the relevant facts have not yet been determined.

Cato’s brief also explains the fallacy of the notion that case law can provide police with “fair notice” about where the line is between lawful force and excessive force in a given situation, given that police don’t read judicial opinions and would rarely if ever have the ability to recall, assess, and apply controlling case law in the midst of pursuing a suspect, making an arrest, or making any of the countless other split-second decisions they are often faced with in the field. Moreover, the challenge of determining whether it was “clearly established” that an officer used excessive force is only compounded when there is disagreement about what the officer actually did.

Finally, while appellate courts are bound to apply Supreme Court precedent even when it doesn’t make sense, they need not exacerbate the problem by providing en banc review of manifestly unripe appeals like this one. Accordingly, the Fifth Circuit should deny Officer Nissen’s petition and remand the case to the trial court so the relevant facts can be determined by the citizen jury to which the Constitution assigns that task.