Obama, Supposedly a Lawyer,

should take a look at 18 USC, Section 713 about emblems, insignias, and names:

Sec. 713. Use of likenesses of the great seal of the United
States, the seals of the President and Vice President, the seal
of the United States Senate, the seal of the United States House
of Representatives, and the seal of the United States Congress

(a) Whoever knowingly displays any printed or other likeness of the
great seal of the United States, or of the seals of the President or the
Vice President of the United States, or the seal of the United States
Senate, or the seal of the United States House of Representatives, or
the seal of the United States Congress, or any facsimile thereof, in, or
in connection with, any advertisement, poster, circular, book, pamphlet,
or other publication, public meeting, play, motion picture, telecast, or
other production, or on any building, monument, or stationery, for the
purpose of conveying, or in a manner reasonably calculated to convey, a
false impression of sponsorship or approval by the Government of the
United States or by any department, agency, or instrumentality thereof,
shall be fined under this title or imprisoned not more than six months,
or both.


There is more from the U.S. Code. Note: The link I used yesterday did not work. This is to the site itself, but one can use the search function using 18 USC 713 and find the information.