He categorically stated that such a proposal would reduce the amount of charitable giving. The problem is that he's an academic economist, so I would ask, where's the reference? Sure, the president argued the opposite point over the weekend saying that the state of the general economy is a better indicator for charitable giving than tax deduction status. Both men failed to cite an objective study as evidence.
Perhaps this is a problem with economics as a supposed science, and perhaps that is the part of the primary cause of the horrific boom and bust cycles we see. A high profile academic can go on national business TV with fairly sophisticated viewers and spout his opinion without any compulsion to make his case with a substantive argument or reference.
In medicine, even the least academic practitioner in the most rural locale, speaking to the least sophisticated patient, would likely be able to cite two or three studies published in national referee journals to support placing the patient on the most basic antibiotic or blood pressure medicine.
So why can't we get a little more rigorous in dealing with the financial crisis that ate the world?
(Also, Feldstein sat on the AIG board that reviewed their financial products; do you think Joe Kernan could broach that important part of his resume during the interview?)