Why now? Why didn't this come out during the campaign?

He recently agreed to allow the Navy to release his military records. His Yale grades were in those records. A group called the "Swift Boat Veterans for Truth" had been calling for about a year to get Kerry to release his records, claiming they would demonstrate that he served dishonorably. They don't. In fact, the records are so uninteresting that lots of people are wondering why he didn't release them earlier. It might be because he didn't want his Yale grades getting out. Its also possible that he didn't want to set a precident for other politicians.

RE: Kerry's Yale Grades Similar to Bush's