So if congress thought that killing all the old people was good for the general welfare, they could do it? Of course not, you big govt statist. They can contribute to the general welfare while staying in line of the other enumerated powers.
That clause wasnt an all encompassing power. If it was, they wouldnt have needed a constitution.
James Madison 1792
If Congress can employ money indefinitely to the general welfare, and are the sole and supreme judges of the general welfare, they may take the care of religion into their Own hands; they may a point teachers in every state, county, and parish, and pay them out of their public treasury; they may take into their own hands the education of children, establishing in like manner schools throughout the Union; they may assume the provision for the poor; they may undertake the regulation of all roads other than post-roads; in short, every thing, from the highest object of state legislation down to the most minute object of police, would be thrown under the power of Congress; for every object I have mentioned would admit of the application of money, and might be called, if Congress pleased, provisions for the general welfare.
In short, sir, without going farther into the subject. Which I should not have here touched at all but for the reasons already mentioned, I venture to declare it as my opinion, that, were the power of Congress to be established in the latitude contended for, it would subvert the very foundations, and transmute the very nature of the limited government established by the people of America; and what inferences might be drawn, or what consequences ensue, from such a step, it is incumbent on us all to consider.