We're talking about slightly different things.
I agree that the Constitution gives the Executive power over foreign affairs, subject to the funding constraints and other legal constraints imposed by Congress. As such, the President has the power to direct funds for humanitarian relief.
My quibble was that the Constitution doesn't say specifically that taxes may be raised to fund roads or ports or research or ..., but instead talks about generalities ("provide for the common Defence and general Welfare of the United States.")
AFAIK, much of our taxation (sales, income, property) is the same way, with few taxes dedicated to a specific purpose. And even in those cases where the funding is supposed to be dedicated toward a specific purpose (e.g. gas taxes to the Highway Trust Fund; FICA), those funds are quite often borrowed or tranferred to the general fund for the total budget.
I'll bow out now.
Cheers,
Scott.
