A rookie lawyer mistake that I see even experienced lawyers on both sides of the criminal bar make is this: confusing “legally sufficient evidence” with “proof beyond a reasonable doubt”. The prosecutor points to a case saying that similar evidence was legally sufficient as proof that the accused will be convicted; the defense lawyer acquiesces and the accused pleads guilty.

Legally sufficient evidence is the constitutional minimum required to sustain a conviction. The test for legal sufficiency is this: could any rational trier of fact have found the essential elements of the offense beyond a reasonable doubt?

When a court says that the evidence is legally sufficient, it’s not saying that every jury confronted with that evidence would convict, rather it’s saying that a jury could rationally convict.

How is this relevant to a jury? It’s not. A jury charge should never refer to legal sufficiency; a trial court can’t lawfully tell the jury that such-and-such evidence is enough — in Texas, at least, judges are not permitted to comment on the weight of the evidence.

The cases that are worth publishing are the close calls — those in which the lawyer had a straight-faced argument that the State didn’t prove its case. That one jury disagreed, and that a court of appeals upheld the conviction, doesn’t come anywhere close to making a conviction based on similar facts a foregone conclusion. To the contrary, the fact patterns in legal-sufficiency cases are often on the ragged edge of proof.

Just because a jury could rationally convict doesn’t mean that a rational jury would.