The bottom line is simple.
Either we are a nation of laws, or we are not.
If we are, the Constitution is the Supreme law.
It says clearly the US government only possesses certain powers, and each is clearly enumerated therein.
I cannot find the part specifically talking about using tax dollars for charity (or as you may prefer, disaster relief)
Please consider Davy Crockett's "Not Yours To Give".
http://www.house.gov/paul/nytg.htm
Once we make exceptions to laws, the laws become meaningless. Posters here seem to desire some sort of democratic anarchy where the government does whatever most of the voters want them to do, whether or not those proposed government actions are in line with existing law.
I am very troubled by this, but not the least bit surprised by the inevitable willingness of people to gradually trade liberty for security until the will to live freely is but an after thought.