THE NEW REPUBLIC: Making Obama Unelectable: "She needs to convince the remaining uncommitted superdelegates to split for her by about a 2-to-1 margin. The only way she can get a split like that is if she can persuasively argue that Obama is unelectable. And the only way she can do that is to make him unelectable. Some people have treated this as an unfortunate byproduct of Clinton's decision to continue her campaign. It's actually a central element of the strategy. Penn is already saying he's unelectable. It's not true, but by the time the convention rolls around, it may well be."
This analysis says that Clinton's strategy is to trash Obama so badly that by the time the convention rolls around he will be unelectable as president. That leaves her. Charming.