Note that Obama claims graduation not from Columbia University, but specifically Columbia College, supposedly a component thereof. It seems odd that he would have a degree from the college but not the university. Though the original story was that he received a B.A. with major in political science, a recent article claimed he had been awarded a Master’s degree.
Obama almost pathologically twists facts to his immediate advantage — there is likely a half-truth behind this. In searching graduation lists for the possible years, it would be wise to check for the various Obama aliases (Obama, Soetoro, Soebarkah, Steve Dunham, etc.), grad school versus undergrad, some alternative Columbia College program (International Studies perhaps?), etc.
This is all allegation that could have been proven years ago. You go to the school and get the graduation programs, yearbooks, etc... They are kept at every institution. Very easy to check for college vs. University. Local police solve things every day using High School libraries for these items. The colleges can’t hide them. It would take less than 1 hour in the library. Even better, the classmates probably saved their programs. If not, the committee for reunions has master lists. These are things that can’t be deleted.