Jury nullification appeared at other times in our history when the government has tried to enforce morally repugnant or unpopular laws.  In the early 1800s, nullification was practiced in cases brought under the Alien and Sedition Act.  In the mid 1800s, northern juries practiced nullification in prosecutions brought against individuals accused of harboring slaves in violation of the Fugitive Slave Laws.  And in the Prohibition Era of the 1930s, many juries practiced nullification in prosecutions brought against individuals accused of violating alcohol control laws.

More recent examples of nullification might include acquittals of "mercy killers," including Dr. Jack Kevorkian, and minor drug offenders.

Early in our history, judges often informed jurors of their nullification right.  For example, our first Chief Justice, John Jay, told jurors: "You have a right to take upon yourselves to judge [both the facts and law]."  In 1805, one of the charges against Justice Samuel Chase in his impeachment trial was that he wrongly prevented an attorney from arguing to a jury that the law should not be followed. 

Judicial acceptance of nullification began to wane, however, in the late 1800s.  In 1895, in United States v Sparf, the U. S. Supreme Court voted 7 to 2 to uphold the conviction in a case in which the trial judge refused the defense attorney's request to let the jury know of their nullification power.

Courts recently have been reluctant to encourage jury nullification, and in fact have taken several steps to prevent it.  In most jurisdictions, judges instruct jurors that it is their duty to apply the law as it is given to them, whether they agree with the law or not.  Only in a handful of states are jurors told that they have the power to judge both the facts and the law of the case.  Most judges also will prohibit attorneys from using their closing arguments to directly appeal to jurors to nullify the law.

Recently, several courts have indicated that judges also have the right, when it is brought to their attention by other jurors, to remove (prior to a verdict, of course) from juries any juror who makes clear his or her intention to vote to nullify the law. 

Judges have worried that informing jurors of their power to nullify will lead to jury anarchy, with jurors following their own sympathies.  They suggest that informing of the power to nullify will increase the number of hung juries.  Some judges also have pointed out that jury nullification has had both positive and negative applications--the negative applications including some notorious cases in which all-white southern juries in the 1950s and 1960s refused to convict white supremacists for killing blacks or civil rights workers despite overwhelming evidence of their guilt.  Finally, some judges have argued that informing jurors of their power to nullify places too much weight on their shoulders--that is easier on jurors to simply decide facts, not the complex issues that may be presented in decisions about the morality or appropriateness of laws.

On the other hand, jury nullification provides an important mechanism for feedback.  Jurors sometimes use nullification to send messages to prosecutors about misplaced enforcement priorities or what they see as harassing or abusive prosecutions.  Jury nullification prevents our criminal justice system from becoming too rigid--it provides some play in the joints for justice, if jurors use their power wisely.