The concern with that would be that if you were to guarantee or provide yourself a loan, and if that loan was not repaid, it would essentially turn into a donation. That donation would be over and above the donation limit currently set at $1200. If that loan is at the donation limit amount, it's deemed a donation at some point after default and essentially that takes care of it. If it's over that amount, then you deem it a donation and then they have over-contributed. Also, some people may not be able to provide themselves a line of credit, $20,000 or $30,000, or whatever amount you may say. This really levels the playing field to a point where everybody has equal access. In your scenario, you would have to assume that the person has the money to provide for themselves. Even if you're guaranteeing something, you have to guarantee it on something, and some people may not have that ability. This is really about taking that advantage away from wealthy individuals.
On October 18th, 2012. See this statement in context.