united-states
Some U.S. states, including Ohio, until 2019 historically required that self-defense be proved as an affirmative defense by a preponderance of the evidence. At this point, however, all U.S. states require that it be ruled out beyond a reasonable doubt by the prosecution at trial if facts raising the issue are presented, although some states allow for the case to be dismissed prior to trial if this affirmative defense can be established in an evidentiary hearing before a judge by a preponderance of the evidence.
In the end analysis, this changed when Ohio changed its rule in 2019, but there is still a role for the preponderance of the evidence rule, which continues to apply in many states as the standard required to dismiss a case on self-defense grounds prior to trial, as explained at the link:
[H]istorically, the affirmative defense has shifted the burden of proof.
Normally, the burden of proof is on the accuser–the state or the
plaintiff–to show that a wrong was done by the defendant. Here, the
defendant has said, “Yeah, I did the thing you say was wrong. I’m
saying I was right to do it, and therefore should be held harmless.”
I always invoke the balance test from two great legal scholars, in my
opinion, one being, Henry Campbell Black. He was the author of Black’s
Law Dictionary which is still the standard today. If you look up
“affirmative defense” in Black’s Law Dictionary it will clearly state,
the affirmative defense shifts the burden of proof to the defendant.
Now, the other citation is from a man I consider a great legal scholar
of our time on this topic, Andrew Branca, author of Law of
Self-Defense. When Andrew meticulously went through the laws and the
rules of the courts in all 50 states, he found what I did way back in
the ‘70s, when I did that for my first book, In The Gravest Extreme
that came out in 1980.
What the law says is that once self defense is on the table and the
jury is allowed to hear the argument or the judge accepts that it is a
possibility, at that point in a criminal case the burden of proof
shifts back to the state to prove that it was not self defense. The
one exception for many, many years was the state of Ohio, which said
in the black letter law in a self-defense homicide or a self-defense
harmful action the burden would be upon the defendant to show that it
was self defense. . . .
A quick commentary on the standards of proof may help. A guilty
verdict demands that you be found guilty beyond a reasonable doubt.
When self defense is on the table, the standard of proof is to a
preponderance of evidence to show that it was self defense. That
remains the standard today in some of the states that have the
so-called stand your ground option. That is a misnomer: really, it is
simply a pre-trial hearing in which the judge determines whether or
not there is enough evidence to show that you are likely to be guilty.
If in that hearing, you can show to a preponderance of evidence–more
likely than not–that it was self defense, in those states the judge
has the power to permanently dismiss the case, dismiss it with
prejudice, and end it right there.
Let’s go back: so, if we have self defense on the table, where is the
burden of proof? For self defense to be on the table at all–for the
judge to allow your attorney to say “self” and “defense” in the same
sentence–prior to trial, you will have to show some corroboration that
you are not just saying, “Take my word for it! It was self defense.”
The required corroboration is called “burden of production.” When I
hear “burden of production,” to me the operative term is “burden.” In
and of itself, right there, it is a burden of proof element from the
get-go. Once self defense is on the table, the judge is going to tell
the jury that the prosecution has to prove beyond a reasonable doubt
that it was not self defense.
Then, as the instructions go to the jury, and as the door closes on
that deliberation room theoretically, at law, the burden is back on
the opposing side, on the prosecution.
Note also, that any U.S. state could return to Ohio's pre-2019 rule that a defendant has to prove self-defense by a preponderance of the evidence at trial in the future. There is no national rule of constitutional law on this point. The change in Ohio's rule was due to a new criminal procedure statute and not a court holding that its old rule, which applied for many, many decades to countless cases without falling to a constitutional challenge, was unconstitutional.
