Timing Your Commute

Why do Governors always seem to wait until the last possible minute to commute the sentences of convicted criminals?

Does it really take that long to review a case? Are they waiting for further exculpatory evidence? Is crafting a budget a higher priority? Does the victim's family frequently lobby for an expedited execution? Does it take a long time for a public outcry to develop in support for the prisoner?

Or does the drama build the closer the execution comes giving the granter of clemency an almost God-like status as someone who holds life and death in his or hands? Does a governor become more merciful the closer the death of the inmate becomes?

If that's the case, isn't that kind of cruel and/or unusual?

Just a thought ...