I'd love to hear the legal theory behind that.
Actually, it's not that much of a stretch, considering the Constitutional principles involved. The USC prohibits emoluments to our elected and appointed federal officials. There's a strong case to be made that the Nobel Prize is a kind of emolument.
For this reason and a few others (mostly surrounding the fact it's a prize given by a foreign power), Teddy Roosevelt elected to wait to accept his Nobel Prize until after he actually left office. Why this wasn't spoken about more when Obama won his, is a mystery - not really, the press wasn't going to rain on his parade. More can be found below...