“Measles Outbreak”–Blaming the Unvaccinated?

The Press and Newscasts are making a meal of the story of “measles outbreak” in the USA. Scientists and lawyers argue that parents who don’t vaccinate their children should go to jail; that they always commit a tort; and that they are making a negligent, unreasonable and reckless decision under the law. President Obama stated that there is no reason to not vaccinate, while Senator Rand Paul wants to give parents the freedom to decide. What are the facts? Are vaccines harmless? Are they always effective? Why do properly vaccinated persons contract measles? Should we accept the position of those who oppose vaccination for religious or medical grounds? What are some of the reasons, and who are among those who decide against vaccination?