I tend to be against politics for advancing liberty. I am happy that Ron Paul is running for president, but not because I expect him to win. He is using his platform to spread the message of liberty to millions of people. So while he is using a political forum to do this, it is his educational influence that is most important, as thousands of more libertarians sprout up every week.
The only way to bring about lasting change in favor of liberty is by changing the hearts and minds of the people. If a majority or strong minority of the American people withdraw their consent from the government, then the government will weaken and may eventually even collapse if the sentiment is strong enough.
One way that Americans can impose an almost immediate effect is by using the power of the jury. In any court case that involves a jury, it is up to the people on the jury to decide the verdict. It is basically out of the control of the judge and the government in general at that point. While you will not be told this as a juror, it is not only your responsibility to judge the facts of the case and determine if the person violated the law, but it is also your responsibility to judge the fairness of the law in question.
If you, as a juror, believe that a law is unjust, it is your right to use jury nullification. You can essentially nullify the law, or at least in regards to the person on trial.
Some libertarians will point out that jury duty itself is anti-liberty, because you are essentially being forced to serve on the jury. This is a valid point, but in a libertarian society, I believe most people would be willing to serve on a jury, if in fact juries existed. Even more so, I believe most people would be willing to serve as witnesses. If someone declined to serve as a witness to either convict or absolve someone from a crime, then that person could be blacklisted by the private sector. If a crime were committed against someone refusing to be a witness, then maybe that person would not have the same redress as others because they had previously refused to serve as a witness. Regardless, this is a subject for another day.
Regardless of whether you think jury duty should be mandatory, libertarians should take advantage of being called for jury duty, particularly for cases that involve a victimless crime.
Imagine a world where 20% of the population is made up of principled libertarians. If you get a couple of people on each jury that is willing to use nullification, convictions for victimless crimes will become really difficult. Some "crimes" to be nullified could include drug use, tax evasion, insider trading, prostitution, and selling raw milk. I'm sure you can think of many others if you are a libertarian.
Right now, most people would be terrified to go in front of a jury on a tax evasion charge. They end up doing a plea bargain so that they can serve less time in prison or pay a smaller penalty. But what if public sentiment changed so much that there would be a good chance of an acquittal? Imagine if juries started acquitting for the majority of tax evasion cases or drug cases that didn't involve violence on the part of the accused.
Even if juries were hung, it would still be a blow to the prosecution and the law in general. If enough people started being acquitted of drug use and tax evasion, then more people would start to openly defy these laws. Eventually, the government would see these laws as unenforceable and these laws would, in effect, be nullified.
If you have the opportunity to serve on a jury, you should take it. You could make the difference in someone's life and you could send a message. You will be asked questions before being picked for a jury. You should not lie, but you can try your best to avoid answering questions or volunteering too much information. If you do get picked for a case that happens to involve a victimless crime, you will have to stay strong against the other jury members. You do not have to change their minds. You do not have to give a reason for voting to acquit. You can simply say that that is how you will be voting.
Jury nullification can be a powerful tool for libertarians. We don't need to elect the right politicians to change the law. We just need to stop locking people up for violating laws that shouldn't exist in the first place.