Wait, wait, wait.
First of all, it would not be the upset of the year. This race went from very competitive to kind of competitive and back to very competitive. Tester was the underdog at one point too.
A lot of Democrats had this race in their safe column. They wrote Burns off very quickly and hailed Tester as their saving grace. Thus I would consider it a rather large upset, at least more so than anything else that could possibly happen at this point.
Neither candidate really urks me either way. What does is the thought of a Democratic controled senate. If Tester loses, this fear of mine would be layed to rest. Thus Burns could potentially be a GOP hero if he wins.