Article I, Section 9, of the Constitution, the emolument clause, clearly stipulates: "And no Person holding any Office of Profit or Trust under them, shall, without the Consent of the Congress, accept of any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince or foreign State."
An opinion of the U.S. attorney general advised, in 1902, that "a simple remembrance," even "if merely a photograph, falls under the inclusion of 'any present of any kind whatever.' " President Clinton's Office of Legal Counsel, in 1993, reaffirmed the 1902 opinion, and explained that the text of the clause does not limit "its application solely to foreign governments acting as sovereigns." This opinion went on to say that the emolument clause applies even when the foreign government acts through instrumentalities. Thus the Nobel Prize is an emolument, and a foreign one to boot.
Second, the president has indicated that he will give the prize money to charity, but that does not solve his legal problem. Giving that $1.4 million to a charity could give him a deduction that would reduce his income taxes by $500,000 -- not a nominal amount. Moreover, the money is not his to give away. It belongs to the United States: A federal statute provides that if the president accepts a "tangible or intangible present" for more than a minimal value from any foreign government, the gift "shall become the property of the United States."
So he's accepting an award from a foreign government (i) to which he is not entitled, (ii) the acceptance of which is clearly unconstitutional and (iii) monies which he is accepting and then donating to charity - monies that are not his to give away since they belong to the U.S. Treasury!
Didn't our president advertise himself as a "constitutional lawyer" during the campaign. Surely he knows he is committing clearly impeachable offenses here. Or does he even care?