According to the National Enquirer and The New Republic, Track Palin (Sarah's oldest) vadalized school buses and is (or has been) an oxycontin addict.
From Margo Howard, quoted in The New Republic.
It would have far more factual validity for Obama, or a surrogate, to publicize the fact that Track, the kid who joined the Army, did so because a judge told him it was that or jail due to his dealing drugs.
Besides, Sarah started it (I can call her Sarah, 'cause she's all folksy, yebetcha) by using her kids as political props at every possible occasion.
Lots of additional speculation here.
From the New York Times, some exculpatory info: though notice that Levi Johnston has now dropped out of High School and hockey.
In the end, hockey did not work for Levi Johnston. His grades slipped, he left school and he quit playing altogether.
The dream for Track Palin unraveled, too, starting when he separated his shoulder in Michigan. By March 2007, he was back with his family and that spring graduated from Wasilla High School. He had shoulder surgery, and the Avalanche offered him a playing slot, said the team’s general manager, Jamie Smith.
But that summer, Mr. Smith said, Track Palin called him and said that his shoulder was not better and that he was going to enlist in the Army instead.
Here's Ancorage TV on the subject: