http://www.fec.gov/pages/brochures/foreign.shtml
The Federal Election Campaign Act (FECA) prohibits any foreign national from contributing, donating or spending funds in connection with any federal, state, or local election in the United States, either directly or indirectly. It is also unlawful to help foreign nationals violate that ban or to solicit, receive or accept contributions or donations from them. Persons who knowingly and willfully engage in these activities may be subject to fines and/or imprisonment.