The American criminal justice system can be dizzyingly complex but a few simple rules underpin the whole system.

The biggest one: a criminal defendant is presumed innocent and the government has to prove the defendant guilty beyond a reasonable doubt. This means that the defendant does not have to prove innocence. The defendant could literally—and sometimes does literally—nothing the whole trial, and still wins

Of course, most defendants do something in their own defense, but it may not involve testifying.

This is what happened in State v. Tullar, a Court of Appeals case decided last week.

The Battle over Jury Instructions

The State charged Tullar with assault in the second degree in Okanogan County Superior Court for fighting with another inmate (Cook) at the City Jail. As with most fights, the evidence conflicted, but it seems that Cook challenged Tullar to a fight in Cook's cell and Tullar accepted. During the fight, Tullar fractured Cook's nose and left eye socket.  

Tullar did not testify at trial but two inmates testified for him. They testified that Tullar went inside Cook's cell first, and immediately Cook put Tullar in a chokehold. Tullar fought back and escaped the chokehold. They kept punching each other until Cook gave up. One of the State's witnesses (a correctional officer) testified that Tullar had marks on his neck.

Jury instructions matter – a lot. Most jurors aren't lawyers, so we don't expect them to know that much about criminal law—or any of it. That's why judges instruct jurors how to decide the case. Obviously, what jury instructions are given determine how a jury views the case. Not surprisingly, the battle over jury instructions is huge.

In Washington, a defendant can use force to defend himself if he is about to be injured, so long as he uses no more force than necessary. Self-defense, therefore, is a lawful defense to assault. To establish self-defense, the defendant must present evidence that he reasonably believed force was necessary when he committed the assault.

Tullar obviously wanted the trial judge to instruct the jury on self-defense. The State objected, arguing that Tullar himself did not testify about his subjective fear during the fight. The trial judge agreed with the State and did not give the instruction.

The jury found Tullar guilty and he appealed.

Court of Appeals: Tullar's jury should have been instructed on self-defense

The Court ruled that the trial judge should have instructed the jury on self-defense.

A trial judge must instruct the jury on the defendant's theory of the case if at least some evidence presented at trial supports this theory. Per the Court of Appeals, Tullar presented enough evidence of self-defense. A jury could believe (but maybe wouldn't) that Cook started the fight when he put Tullar in a chokehold.

That Tullar himself did not testify is irrelevant. The evidence for self-defense can come from any witness—even the State's own witnesses. As the Court put, the defendant just has to produce some evidence “from whatever source” to prove that he reasonably feared harm.

A defendant isn't guaranteed to get a conviction overturned, however, simply because the trial court didn't instruct the jury on the defense theory. But if the failure to instruct is “prejudicial” to the defendant, it will get a new trial.

Without a self-defense instruction, Tullar's changes of winning were slim to none. As the Court of Appeals succinctly put it: “Tullar's only argument for acquittal was that he lawfully defended himself. The trial court's decision not to instruct on self-defense virtually guaranteed Tullar's conviction.”