A minor puzzlement is why a few partisan actors continue to toy with Alvin Greene.  Perhaps the summer season is idle for the relaxed partisans in the Carolinas.   Mr. Greene remains a mystery--but not a profound one.  His military service, his inventiveness, his spontaneous enthusiasm, all point to a self-confident, earnest opportunist.   There is little suggestion that he has been mentored, or that he has any experience as a politician.  He brings an air-guitar enthusiasm to a sober role.  The South Carolina Democratic Party looks not to be helping him or even especially interested in the spotty campaign.  The prominent James Clyburne of the House asserts that he will not support Greene.  Sixty days to go.  What I like about Mr. Greene is that he is relentlessly game.  The pending charges against him for sexual misconduct are serious, yet he remains an innocent accused.  Something about the way Greene has pushed himself into the conversations feels like a throwback to the early 19th century, an age of amateur politicians who were suspicious and charismatic at the same time.  Then again, this is the age of celebrities called Gaga and Levi Johnston, and so perhaps it is also Alvin Greene Nation.  Perhaps Alvin Greene is just a random, youthful, goofy and not unhumble performance artist with the sort of troubles that come to solitary young men.  The $10,000 registration fee in order to become a candidate for the Senate on the Democratic line remains the centerpiece of the mystery.