It seems to me that the issue regarding the meaning of the general welfare clause can be solved with Justice Marshall's argument in Marbury v.. Madison.

It cannot be presumed that any clause in the Constitution is intended to be without effect, and therefore such construction is inadmissible unless the words require it.

To argue that the general welfare clause grants some unnamed powers to Congress would in effect nullify the 10th amendment and the enumerated powers. Therefore, the clause cannot be interpreted to grant any powers other than those enumerated in the Constitution.

The problem for me arises because of the authorization given to Congress to enact legislation in support of the enumerated powers granted to it by the Constitution. I sense that there is alway a danger here that a law so enacted could go beyond the limits intended by the framers of the Constitution.