John Glenn never paid off debts from his ill-fated 1984 presidential run as he was NOT ALLOWED TO under federal elections commission rules. He could not even reach in his own pocket and pay it or try to raise money for that purpose. It is all based on a window of opportunity for raising and paying, and the giving limits.
http://www.npr.org/2011/07/05/137615746/presidential-campaign-debt-can-linger-for-decades
http://abcnews.go.com/Politics/OTUS/campaign-debt-outlives-presidential-race/story?id=17743398
I had a hunch that there was more to the story than simply refusal to pay. How often does such a problem arise because of bureaucratic over-regulation? In my work experience, I have seen several incredibly easy and logical fixes to problems which couldn’t be done because of some rule or policy which was often designed to prevent a real problem but had unintended consequences.