Why does the legal system allow lawyers to give purposely confusing instructions to jurors?
<p>I just read <a href="https://law.stackexchange.com/a/4560">this answer to a popular question here</a>, where it explains why lawyers aren't allowed in juries most of the time; here's an excerpt: </p>

<blockquote>
  <p>If a lawyer is in the jury, that person will undoubtedly be able to
  explain exactly what the law requires for a finding, or exactly why a
  certain finding should be had. They will advocate one way or another;
  this is undeniable. The instructions are purposefully confusing. The
  reason is this: when we fight over jury instruction, inherently, one
  of us will want an instruction that is hard to understand, for a lay
  person. This is because we want them to apply the law as it is
  commonly (mis)understood, not as it truly is, because that's not good
  for our case.</p>
</blockquote>

<p>And a comment sums the answer up nicely:</p>

<blockquote>
  <p>tl;dr jury trials have become a theater where attorneys on each side
  will try to confuse the poor laypersons on the jury into voting in
  their favor. Lawyers will typically see through that and negate all
  the showmanship that the attorneys will do.</p>
</blockquote>

<p>This is the first I've heard of this, and it seems unethical, unjust, and deceitful, all words that one would expect never to be able to use when talking about the legal system. </p>

<p>Why is this allowed? Why doesn't the law ensure that jurors, laymen and experts alike, are given clear and concise instructions? </p>

<p>While it is true that jury instructions are typically less than optimal, it is ideological hyperbole or cynicism to claim that instructions are <em>purposely</em> confusing. The ultimate source of the confusion is that the legal system has to assume (pretend) that it has clear-cut rules that any reasonable person can easily understand and automatically apply. In order to maintain uniformity of the law, there is an externally-defined instruction that a judge may read (rather than giving <em>his</em> personal spin on what "reasonable doubt" means or what the relationship is between "reasonable doubt" and convicting a defendant). Once the relevant body of government (committee of judges and lawyers) has established the apparently correct formula for expressing the applicable legal concept, they don't mess with it, until SCOTUS overturns decisions enough times based on crappy instructions.</p>

<p>Legal professionals are trained to carefully scrutinze language so as to achieve a single interpretation of a given clause (never mind the fact that there turn out to be many such interpretations). Since they can apply these interpretive rules, it is assumed that anyone can apply them. But in fact, we know that people <em>don't</em> just use literal semantic principles to reach conclusions – but the law resist pandering to that imperfection in human behavior.</p>

<p>There is a huge literature on problems of jury instructions, some of the better of which relies on psycholinguistic experimentation to establish that a given instruction is confusing or gives the wrong result. See for example Solan's "<a href="http://brooklynworks.brooklaw.edu/cgi/viewcontent.cgi?article=1293&amp;context=faculty" rel="noreferrer">Refocusing the burden of proof..</a>" (and references therein) that addresses the problem of the "beyond a reasonable doubt" instruction, which has the unintended consequence of implying that the defense has an obligation to create a doubt (which is not the case, and allows conviction if there is the weakest imaginable evidence which hasn't been refuted). But who gets to decide what the improved instructions should say? The instructions have to correctly state what the law holds (where "the law" means not just statutes, but the trillions of relevant court decisions and applicable regulations). Thus there is massive inertia, and improved jury instructions will not come about quickly.</p>

<p>Jurors are given clear and concise instructions; that is what the judge's summing up is for.</p>

<p>In a jury trial the judge's job is to decide what the law is and the jury's job is to decide what the facts are. The judge will instruct the jury (essentially) that if you believe the facts are A the law requires an acquittal and if you believe they are B then a conviction is called for.</p>

<p>The parties to the case will argue both the law and the facts: in theory the law is to convince the judge and the facts to convince the jury.</p>

<p>It's worth noting that this is a common law perspective; other legal systems have different philosophies. Common law is adversarial: accusers must prove their case (to the requisite level); a defendant needs to prove nothing. The law has no interest in the "truth"; that's for philosophy classes, the law is only interested in what can be proven.</p>

<p>I give you a couple of problems with lawyers on juries. In criminal cases, Jury nullification is perfectly legal and has a long history. Some states include jury nullification in their instructions while others do not. A lawyer on a jury is going to know about jury nullification whether instructed or not.</p>

<p>In New Jersey, the judges are prohibited from giving the apportionment of liability rules to the jury (i.e., a party liable for less than some threshold cannot be held liable for the entire judgement). A lawyer would know those rules and could give them to the jury.</p>

united-states jury