As a public office holder, or a candidate for public office, I affirm that:
A government without limits is a tyranny.
The Tenth Amendment defines the total scope of federal power as being that which has been delegated by the people to the federal government in the Constitution, and also that which is necessary and proper to advancing those powers specifically enumerated in the Constitution of the United States. The rest is to be handled by the state governments, or by the people themselves, as they determine.
In order for a federally-exercised power to be "necessary and proper" it must be a) something that, without which, would make the enumerated power impossible to exercise, and b) a lesser power than that which has been enumerated
The "Interstate Commerce Clause" in Article I, Section 8 of the Constitution, does not permit Congress to regulate matters that merely affect commerce among the States. It only permits Congress to regulate trade among the States.
The phrase, "general Welfare," in Article I, Section 8 does not authorize Congress to enact any laws it claims are in the "general Welfare" of the United States. The phrase sets forth the requirement that all laws passed by Congress in Pursuance of the enumerated powers of the Constitution shall also be in the general Welfare of the United States.
The federal government is not authorized to tax the People to raise monies for unconstitutional purposes. Likewise, the federal government is not authorized to condition funding to State or local governments on compliance with mandates which require them to do what the federal government is not authorized to do directly.
Source: The Tenth Amendment Pledge 10-10th-WP on Jul 4, 2010