For someone who is normally strict a constructionist, your stance on public education is puzzling.

It is mandated, first and foremost ,in the constitutions of the many states. This is the ultimate expression of states' rights, as Washington D.C. has helped enforce educational requirements in the state constitutions. Just as certain federal agencies are mandated through the US Constitution and taxes/revenue collection methods are mandated to maintain them, education requirements and taxes to fund them are mandated in state constitutions.