This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.
Q: Passage: Steven Barkan writes that if defendants plead not guilty, "they must decide whether their primary goal will be to win an acquittal and avoid imprisonment or a fine, or to use the proceedings as a forum to inform the jury and the public of the political circumstances surrounding the case and their reasons for breaking the law via civil disobedience." A technical defense may enhance the chances for acquittal but make for more boring proceedings and reduced press coverage. During the Vietnam War era, the Chicago Eight used a political defense, while Benjamin Spock used a technical defense. In countries such as the United States whose laws guarantee the right to a jury trial but do not excuse lawbreaking for political purposes, some civil disobedients seek jury nullification. Over the years, this has been made more difficult by court decisions such as Sparf v. United States, which held that the judge need not inform jurors of their nullification prerogative, and United States v. Dougherty, which held that the judge need not allow defendants to openly seek jury nullification.
A:
What defense was used by Steven Barkan?