[rayiner]

That makes it seem like federalism is a procedural issue orthogonal to any particular substantive policies. But the US is, Constitutionally, an economic free trade zone. As a result, states cannot use the most potent economic tools to ensure enforcement of their laws. Even if the majority of people would prefer to have environmental or worker protection laws, a minority of people in a few states can create a nationwide race to the bottom.

As a practical matter, saying that some issue is the proper domain of the states is equivalent to saying it can't be effectively regulated at all.

And it's not like the framers were unaware of that dynamic. They empowered the federal government to regulate interstate commerce precisely as a foil to the prohibition on states to do so.

[mstodd]

No, saying that an issue is for the states to decide is simply acknowledging that US citizens are individuals, and they know better than the Federal government what they want. Regulation at the Federal level removes choice and freedom.

[rayiner]

You can't enforce many regulations at the state level, even if people want them, because the Constitution forbids discriminating against out of state commerce or citizens. If Californians wanted to have single payer health care, their system would be very susceptible to abuse because people should could cross the border when they got sick. Then Arizonans get the best of both worlds--they don't have to raise taxes to pay for healthcare, but they can still get the service if they need it. Same thing with environmental regulations. Even if everyone in California voted to have environmental regulations, that just creates an opening for goods manufactured in environmentally harmful ways in Arizona to undercut California goods in price.

Citizens don't really have the freedom to choose on issues like that unless they have the freedom to close their markets to people who do not play along. The Constitution takes away that freedom.