Your honor, when my client clobbered his wife over the head with a Louisville Slugger, he thought it was a Nerf product.
MISTAKE OF FACT!
It actually could be, but it would need to be backed by credible evidence, such as the defendant was at the time in the midst of a 106 degree fevered delirium. That would go a long way to satisfying the preponderance of the evidence test regarding the claim that he believed he was holding a Nerf bat. It would be up to the jury to make that credibility determination.
Short of lots of strong evidence that this was actually his belief, however, no, that would not be an acceptable defense, since it would lack credibility.
