Obama has not released his record at columbia but he didn't even make honors (Cum Laude) which at the time was a GPA between 3.2 and 3.4. He thus had under a 3.2. I applied to all the major law schools and as a Yale Undergraduate, I knew that white males who did not have at least a 3.7 had less than a ten percent chance at admission into harvard law and that was with the sort of board scores I had (which was 782 on the the then 800 scale). A white male with under a 3.2 at Columbia getting into Harvard law was unheard of -that would not get you into the schools ranked right below Harvard either (Duke, Penn, Cornell, NYU, UVA, Columbia).
SO its almost certain that Obama's race got him into Harvard.
Romney went to stanford where he was top of his class. He took a leave of absence for mission work and then married and moved to Utah where he enrolled in BYU and graduated FIRST in his class. His academic record was consistent with those I knew at top law schools.