Regarding the general welfare phrase, James Madison addressed this question in 1817 in vetoing a bill for internal improvements. He said, "To refer the power in question to the clause 'to provide for the common defense and general welfare' would be contrary to the established and consistent rules of interpretation, as rendering the special and careful enumeration of powers which follow nugatory and improper. Such a view of the Constitution would have the effect of giving to Congress a general power of legislation instead of the limited one hitherto understood to belong to them. . . ."
Clarence B. Carson, A Basic History of the United States, Volume 5: The Welfare State 1929-1985, pg.61-62