1300 is on the low end of the spectrum for Cornell, isn't it? It can mean one of several things. The first thing that comes to mind is that it means you come from a weak school so your high gpa isn't very impressive in that context.
Low GPA/High SAT implies that you are lazy, but it's not the SAT score that will keep you out. It's the low GPA that will do that. If anything, a high SAT in that situation would help because it means that you have potential.
In the end, SAT doesn't really mean much. Do decent and you'll be ok. They really do look at stuff like your course selection, recommendations, ECs, etc. These "soft factors" are highly underrated by seniors.