I like Madison, he had lots of good ideas. And in fact his statement is more or less true as far as it goes. However, it is also true that even in Madison's day the executive had the power to make binding treaties with other governments (Article II, section 2) that could indeed require the expenditure of funds, deployment of troops, or whatever other obligations the treaty required.
By virtue of the US participation in various world bodies such as the UN, the executive can and does, with the advice and consent of the Senate, make such treaties. Additionally, as commander in chief the executive has the authority to order troops into the field for such purposes as the executive believes are necessary for the security of the United States.
That is more than enough authority for the executive to send troops to Haiti and to specify that funds be spent to do so as well as providing humanitarian aid under the auspices of our UN agreements.
And this is true even without getting into a discussion of the the differences between the constitution as it is in 2010 vs how it stood in 1789.
Was there some point you were trying to make here?