I had thought there was, as evidenced by prominent notices at Boris Johnson's (now Mayor of London) webpage, stating that foreign campaign contributions were not accepted.
Similarly, I'm seeing this at the FEC's site:
Quick Answers-General Questions
Foreign nationals are prohibited from making any contributions or expenditures in connection with any election in the U.S. Please note, however, that "green card" holders (i.e., individuals lawfully admitted for permanent residence in the U.S.) are not considered foreign nationals and, as a result, may contribute. For additional information, consult our "Foreign Nationals" brochure.
*************
I would be interested in learning how this happened, given these prohibitions.
Enchante, the Obama campaign brags all the time about the huge number of small contributions they get from the “grass roots.”
I have long suspected that there is some kind of scam going on. This would seem to support that suspicion.