Before you decide whether you like or dislike Whitman's plan, it's helpful to put the issues in a more manageable context. For this illustration, let's assume we've agreed to send our newborn to Princeton. Then, the family car breaks down.
College is paid for.
That answer is easy. Whitman's plan faces the same possibility, even though it is being touted as the total needed to pay pension obligations for the next 60 years. You still have to pay Princeton the full cost of tuition. Ordinarily, because pension payments are made over many years, a decline in the stock market would not be so troubling. That's because much of the pension money would be invested after such a decline, enabling the pension fund to ride the stock market back up.