I am of the firm opinion that the federal government should be a lot smaller, and that the federal government acts illegally every day when it does a lot of the "general welfare" things that the Tenth Amendment prohibits. People in favor of the status quo point to the "general welfare" clause of Article I, Section 8 of the Constitution, saying that this allows the federal government to do anything in regard to the general welfare. But that must be understood in light of the context, of the intent.
James Madison wrote in Federalist 45:
The powers delegated by the proposed Constitution to the Federal Government, are few and defined. Those which are to remain in the State Governments are numerous and indefinite. The former will be exercised principally on external objects, as war, peace, negociation, and foreign commerce; with which last the power of taxation will for the most part be connected. The powers reserved to the several States will extend to all the objects, which, in the ordinary course of affairs, concern the lives, liberties and properties of the people; and the internal order, improvement, and prosperity of the State.
The operations of the Federal Government will be most extensive and important in times of war and danger; those of the State Governments, in times of peace and security. As the former periods will probably bear a small proportion to the latter, the State Governments will here enjoy another advantage over the Federal Government.
If that is not enough -- some people still try to claim that regardless of what Madison said the purpose of the Constitution was, it does not nullify the blanket language of "general welfare" -- some dozen years later, in the The Virgina Report, he wrote:
In the "articles of confederation," the phrases are used as follows, in Art. VIII. "All charges of war, and all other expenses that shall be incurred for the common defence and general welfare, and allowed by the United States in Congress assembled, shall be defrayed out of a common treasury, which shall be supplied by the several states, in proportion to the value of all land within each state, granted to, or surveyed for any person, as such land and the buildings and improvements thereon shall be estimated, according to such mode as the United States in Congress assembled shall from time to time direct and appoint."
In the existing Constitution, they make the following part of Sec. 8, "The Congress shall have power to lay and collect taxes, duties, imposts, and excises, to pay the debts, and to provide for the common defence and general welfare of the United States."
This similarity in the use of these phrases in the two great federal charters, might well be considered, as rendering their meaning less liable to be misconstrued in the latter; because it will scarcely be said, that in the former they were ever understood to be either a general grant of power, or to authorize the requisition or application of money by the old Congress to the common defence and general welfare, except in the cases afterwards enumerated, which explained and limited their meaning; and if such was the limited meaning attached to these phrases in the very instrument revised and remodelled by the present Constitution, it can never be supposed that when copied into this Constitution, a different meaning ought to be attached to them.
I weep over the part about "rendering their meaning less liable to be misconstrued."