What is the defense of duress?
In order to establish a defense of duress, an accused individual must show that he acted under an immediate threat of death or serious bodily injury, that he had a well-grounded fear that the threat would be carried out, and that he had no reasonable opportunity to escape or inform the police. This defense is also available when the threat of immediate serious harm is directed at a third person and the accused acted unlawfully in order to protect that person.

What is the defense of insanity?
It is a defense to a prosecution under any federal statute that, at the time of the commission of the acts constituting the offense, the accused, as a result of a severe mental disease or defect, was unable to appreciate the nature and quality or the wrongfulness of his acts. Mental disease or defect does not otherwise constitute a defense. The accused has the burden of proving the defense of insanity by clear and convincing evidence.

What is the good-faith defense to a charge of intent to defraud?
One who expresses an honestly-held opinion or an honestly-formed belief cannot be charged with fraudulent intent even though the opinion turns out to be erroneous or the belief is mistaken. Similarly, evidence which establishes only that a person made a mistake in judgment or an error in management or was careless does not establish fraudulent intent.
However, an honest belief by an accused individual that a particular business venture was sound and would ultimately succeed would not, by itself, constitute good faith if, in carrying out that venture, the accused knowingly made false or fraudulent representations to others with the specific intent to deceive them.

Is ignorance of the law ever a defense?
Yes. Although it is frequently said that ignorance of the law is no excuse, ignorance of the law is a defense to the crime of unauthorized acquisition of food stamps because food stamps are not physically dangerous.

To cite another example, the accused was Yugoslavian and spoke no English. He was prosecuted for attempting to export firearms illegally. He was a seaman who was at port in the United States and was given a form which warned–in English—about the Arms Export Control Act. Because he could not read the form, his conviction for knowingly and voluntarily violating the law was not upheld on appeal.

As a final example, an individual convicted of knowingly and willfully making a false statement was found to be error because the form filled out by the accused (which was the basis of the prosecution) was inherently ambiguous.

What is the defense of mistake of law?
Examples of this defense include the following:
a. It is a complete defense to the crime of filing a false tax return that the accused had a good faith belief that the tax laws had been satisfied even if that belief was not reasonable.
b. In another tax case, the accused—an attorney—relied on the “case-closed” accounting method for reporting his income. Although this was not a valid accounting procedure, the appellate court deciding the case determined that the jury should have been instructed on the attorney’s “uncertainty of the law” defense.

What is the defense of entrapment?
An entrapment defense requires two elements:
Governmental inducement of the crime; and
A lack of predisposition on the part of the accused.
Once the accused presents evidence showing inducement, the burden shifts to the prosecution to prove beyond a reasonable doubt that the accused was predisposed to commit the crime.