Jurors of the Casey Anthony trial felt sick to [their] stomachs after they acquitted Casey Anthony. 

I did not say she was innocent.  I just said there was not enough evidence. If you cannot prove what the crime was, you cannot determine what the punishment should be, said Jennifer Ford, a member of the jury.

Of course, Ford followed her duty as a juror and the law of the United States, which stipulates that guilt must be proven by sufficient evidence.

However, if Ford and her fellow jurors wanted to, they could've rendered a guilty verdict.  It's a method called jury nullification, whereby juries nullify the law in the name of justice.

The US justice system is built upon the premise that a defendant is judged by one's peers, who presumably act as a check against corruption legal government officials (judges, prosecutors, etc) and unjust laws.

Therefore, if the jury thought Casey Anthony was guilty, they could have rendered a guilty verdict in the name of justice through jury nullification, regardless of what the law instructed.

However, I personally don't think Casey Anthony's trial was a good place to invoke jury nullification because the requirement of proving guilt beyond a reasonable doubt cuts down on wrongful convictions and protects minorities from the tyranny of the majority.

Indeed, jury nullification was used by white juries to abuse blacks in the South in the days of Jim Crow.

However, jurors should exercise more often the American right of using jury nullification to protest unjust laws.

One of the most unjust laws currently, in my opinion, is sending people to jail for non-violent drug offenses.  I'm personally against doing drugs, but I think it's a gross abuse of justice to throw a non-violent drug offender in hardened prisons with murderers and rapists.

It destroys the life of the non-violent drug offender and bankrupts the government.  Currently, about 50 percent of the federal prisoners are in for drug offenses.  On some level, 50 percent of our federal tax dollars spent on federal law enforcement, the federal legal system, and the federal prison system is used on enforcing unjust laws on drug offenses.

This is the type of law that American citizens need to nullify.  This is what the Founding Father's intended when they set up the US judicial system.