Obama officials said it should be obvious that it is as much in their campaign’s interest as it is in the public’s interest for fake contributions to be turned back, and said they have taken pains to establish a barrier to prevent them. Over the course of the campaign, they said, a number of additional safeguards have been added to bulk up the security of their system.

In a paper outlining those safeguards, provided to The Washington Post, the campaign said it runs twice-daily sweeps of new donations, looking for irregularities. Flagged contributions are manually reviewed by a team of lawyers, then cleared or refunded. Reports of misused credit cards lead to immediate refunds…

Under current law, there is also very little policing of small-dollar contributions. The false donations uncovered by news outlets or by rival campaigns have all involved more than $200, because those contributions must be disclosed in published reports. The campaigns are not required to share any information about donors who give less than $200. And they are not required to even keep records of donors who give less than $50 — they can even give cash.