George Zimmerman’s criminal prosecution in Ohio might have proceeded very differently than prosecution on the same charges in Florida. The two states have very different burdens of proof regarding self-defense. Had Zimmerman been tried for killing of Trayvon Martin in Ohio, these different standards regarding a self-defense claim might have produced a different result.
Both states put the burden of proof on the prosecution to prove all the elements of a criminal case beyond a reasonable doubt. But what does that mean? The devil is in the details.
Proof beyond a reasonable doubt
Ohio law actually provides an exact standard for proof beyond a "reasonable doubt" which is part of the instructions a judge reads to jurors before they retire to deliberate:
"Reasonable doubt" is present when the jurors, after they have carefully considered and compared all the evidence, cannot say they are firmly convinced of the truth of the charge. It is a doubt based on reason and common sense. Reasonable doubt is not mere possible doubt, because everything relating to human affairs or depending on moral evidence is open to some possible or imaginary doubt. "Proof beyond a reasonable doubt" is proof of such character that an ordinary person would be willing to rely and act upon it in the most important of the person's own affairs.
Proving self-defense in Ohio
The burden of proof is different regarding self-defense in Ohio and Florida. In Florida, the prosecution must disprove that a criminal defendant acted in self-defense, and that proof must be beyond a reasonable doubt.
Ohio doesn’t require the prosecution to disprove self-defense, but instead characterizes self-defense as an affirmative defense. That means that after the prosecution proves that Zimmerman killed Martin, the burden would shift from the prosecutor to the defense team to prove that Zimmerman acted in self-defense - and thus was justified in killing Martin.
While Ohio requires the defense to prove self-defense, the burden of proof is much lower than beyond a reasonable doubt. Instead, the burden is proof by a preponderance of the evidence which in plain English means it is more likely than not that Zimmerman acted in self-defense.
Because Ohio requires the defendant to prove self-defense - but is satisfied by proof of a mere likelihood, self-defense could be more difficult for a defendant to establish in Ohio. That burden of proof on the defendant, albeit slight, could result in a conviction rather than acquittal.