The question is not, “Is the measles vaccine is safe and effective?” (I presume that it is.) The question is, “What are the limits of government power?” A person should not be forced to inject something into their body against their will. Period. Everyone else can take steps to defend themselves. Maybe not perfectly, but that is a price we pay for freedom. Neither government nor any majority should be able to use force against those who are peaceful and honest, and who don’t use any force or fraud against others.