1. What is jury nullification? 

Jurors have the ability to acquit a defendant if the jurors have no sympathy for the government’s position in a particular case.  Jurors may acquit even if they believe that the defendant is guilty of the crime charged.  The jury “nullifies” a law it thinks is immoral or wrongly applied to a particular defendant.

Jury nullification can be (and has been) used for unjust as well as admirable ends. And jury nullification is properly reserved for extraordinary circumstances, particularly ones where they believe important information was kept from them. As one federal appellate court noted with respect to the power to nullify, "[w]hat makes for health as an occasional medicine would be disastrous as a daily diet." After all, a system of justice founded on the rule of law is central to the protection of our most fundamental rights.

2. Do juries have the power to nullify? What is the legal basis for this right?
 
 The right of juries to nullify is grounded in federal case law.  The Sixth Amendment guarantees the right to trial by jury in criminal cases.  In one notable case, the court concluded that the right to trial by jury included the right to acquit the defendant because it had no sympathy for the government’s position.  See:  U.S. v. Datcher, 830 F.Supp. 411 (M.D. Tenn. 1993).  The jury acts as the “conscience of the community,” and the power to nullify serves to “prevent oppression by the Government.”  Id. at 414. 

Courts have recognized that a criminal jury has the right to acquit the defendant, regardless of the strength of the evidence.  For example, in Horning v. District of Columbia, 254 U.S. 135 (1920), the Supreme Court explained that “The judge cannot direct a verdict.”  The jury has the right, the Court continued, “to decide against the law and the facts.”  In another case, U.S. v. Trujillo, 714 F.2d 102, 106 (1983), the court recognized that a jury may deliver a verdict that is at odds with the evidence or the law.  And in Cargill v. State, 340 S.E.2d 891, 914 (1986), the court recognized that a jury possesses “a de facto power of nullification, i.e., a power to acquit the defendant regardless of the strength of the evidence against him.”
 
Two procedural elements protect a jury’s power to nullify.  First, a criminal jury has the right to return a general verdict which does not specify how it applied the law to the facts, or for that matter, what law was applied or what facts were found.  Second, the constitutional double jeopardy standard prevents an appellate court from disregarding the jury's “not guilty” verdict and ordering a new trial on the same charge.  See, for example, State v. Lane, 629 S.W.2d 343, 346 (1982): “There is a concept known as jury nullification-a jury deciding cases in disregard of a law they consider unfair, etc. That is, however, simply a power a jury has because once the verdict is entered it cannot be impeached and the defendant retried. Of course, the common experiences in life of the jurors properly form the background against which people-jurors-view the evidence in a case. Jurors do not come to a courtroom bereft of the experiences of life and are expected to use them as jurors.”

3. How do juries find out about this power?

 This is the tricky part.  Judges and defense attorneys do not have the right to advise the jury about its power to nullify.  The United States Supreme Court held that courts are not required to instruct the jury on its nullification power.  See Sparf v. U.S., 156 U.S. 51 (1895).  This reflects a desire to balance the importance of an ordered system of justice, where communities follow the laws, with the constitutional right of a jury to acquit.
 
Because juries do not have the right to be informed about nullification, they can learn of their power to nullify from sources outside the courtroom, such as articles they may have read or televised legal dramas.

4. How has this doctrine been applied?

 There are many examples of juries interposing their own moral or political judgment in defiance of a law.  In the mid 1800s, juries in Northern states practiced nullification in prosecutions brought against individuals accused of harboring slaves in violation of the Fugitive Slave Act.  Later, during prohibition in the 1930s, many juries acquitted individuals accused of violating alcohol control laws.  In the high profile case of Dr. Jack Kevorkian, the jury acquitted Dr. Kevorkian despite the uncontroverted evidence that Kevorkian had violated Michigan law by helping the deceased commit suicide. 

But jury nullification has its dangers as well.  For example, in the 1950s and 1960s some all-white southern juries refused to convict white supremacists for killing black individuals or civil rights workers despite evidence of the defendants’ guilt.

5. How can this power be used to combat the harms caused by the War on Drugs?

In the prosecution of minor drug offenders who are facing severe punishments, for example, juries could apply intermediate nullification and say that although certain drug possessions should be illegal, the punishments prescribed are too severe.

For medical marijuana cultivators and users, juries could elect to truly nullify the law by returning “Not Guilty” verdicts because they believe that growing and selling marijuana for medicinal purposes should not be criminalized. Similarly, juries may wish to nullify ad hoc in the cases of people convicted of dealing hard drugs (because they think such drug dealing should be illegal and is rightly classified as deserving of a prescribed punishment), but that the punishment is too harsh for particular defendants.

6. Have any states codified this right into statute?
   
The state constitutions of both Maryland and Indiana are explicit about the jury’s right to nullify.  Maryland's constitution provides that, "[i]n the trial of all criminal cases, the Jury shall be the Judges of Law, as well as of fact, except that the Court may pass upon the sufficiency of the evidence to sustain a conviction." Indiana's Constitution states that the criminal jury “shall have the right to determine the law and the facts.”

For more on jury nullification, see "When a Jury Should Just Say No."