I swore an oath to uphold the U.S. and California constitutions. Sometimes, that means voting against “responsible” bills that nevertheless represent government overreach. California’s broad new mandate, that a child cannot attend school unless vaccinated for 10 conditions and “any other disease deemed appropriate,” was such an occasion.

The legislation affects four fundamental rights: to parent one’s children; to refuse medical treatment; to practice one’s religion (for those whose creed genuinely eschews medicine); and to attend school (a unique right recognized in California).

Assuming the government has a compelling reason here — slowing the spread of disease — it still can only infringe these liberties if a law is narrowly tailored and logical, and if no less-restrictive means exist.

Consider the following examples. There are 1.2 million Americans with HIV and 178 this year with the measles. Just as vaccines slow or halt the spread of measles, prophylactics slow or halt HIV.

But could the government mandate that everyone use condoms to stop the spread of HIV? Of course not. Such intimate decisions are not for government to make.

About 56,000 people die from the flu or pneumonia each year. Prohibiting travel and assemblies of anyone suspected of being infected would stop disease transmission, prevent deaths and do much good. But again, because the right to assemble is fundamental, the government could not take it away just because you have the flu.

As an article in the Yale Journal of Health Policy, Law, and Ethics recently noted, court rulings allowing mandatory vaccinations are outdated, narrow and come from a line of precedent that also allowed the government to sterilize those it deemed genetically unfit. Forced-vaccination proponents often say we should “trust scientists.” I do. They would be wise to trust constitutional lawyers.