This allows multiple donations from the same person/credit card, stolen cards and foreign donations. The Obama campaign is not employing the widely used credit card address verification system to check whether the address submitted by a donor matches the address tied to the credit card, an omission that might allow supporters to use a fake identity when contributing. The practice could potentially allow donors in possession of illicitly obtained credit card numbers to exceed the campaign limit, and to permit overseas supporters to contribute. The Mitt Romney campaign does require use of the system and asks the donor to include the three or four numbers- sometimes known as the âCVVâ code â on the back of the card. The code helps determine whether the donor is in possession of the card. The Obama campaign donor page does not have a box for entering the CVV code and does not appear to reject donors who lists addresses different from those attached to the cards. http://www.whitehousedossier.com/2012/04/04/obama-campaign-credit-card-verification/