Liberty is a harder to understand than we assume. It means you can do whatever you want, right? As a matter of fact, it doesn't. We are learning that now as we muddle through the complications of an anti-vaccination movement that has led to a completely unnecessary measles outbreak centered in California. Some parents feel they can do with their kids as they please--but they fail to understand that "liberty" to one person can actually interfere with the liberty of another, such as parents who don't want to have their kids exposed to the risk of measles and other viruses. We have dumbed down the concept of liberty, as I write in this story for Yahoo News--which has garnered several thousand comments. My plea in Liberty for All is for us to return to a richer understanding of liberty and once again properly cultivate this priceless American trait.