Great article at the Tenth Amendment Center by Michael Boldin concerning Health Care nullification:
When a state ‘nullifies’ a federal law or regulation, it is passing legally-binding legislation that makes the federal act in question void and inoperative, or ‘non-effective,’ within the boundaries of that state; or, in other words, not a law as far as the state is concerned.
Current nullification efforts around the U.S. have states passing laws that effectively defy federal laws and regulations on firearms, marijuana, identification cards and more. In 2010, we expect to see similar legislation in response to Health Care, No Child Left Behind, Federalization of the Guard and more.
The most asked question is – once such a law is passed, what next?
Nullification laws imply, per the quote from James Madison in the referenced post that:
state governments not only have the right to resist unconstitutional federal acts, but that, in order to protect liberty, they are “duty bound to interpose” or stand between the federal government and the people of the state.
New Hampshire's House Bill 1648 has some teeth and includes penalties for federal agents. Other legislation is even more severe.
One of my favorites: Myth Busting: the ‘Constitutional Expert’. A must read.
Here is a map of states that are passing, have passed, or killed health care nullification legislation.