For example, let us say that next year, the candidates in the Liberal Party leadership race of December 2006 have all paid off their debts, and no longer owe any money. At that point, there will no longer be any way to make a financial contribution to the 2006 leadership race, because first of all, the race is over. Beyond that, since the candidates are no longer in debt, it is no longer possible to contribute in that way.
On June 18th, 2007. See this statement in context.