The worst-case scenario I can come up with for Democrats in 2008 goes something like this:
1. Obama locks up the nomination
2. The press suddenly realizes the Tony Rezko story (see here and here) is worth looking at after-all.
3. The trial becomes a circus, with Obama forced to testify.
4. John McCain plays the race card.
5. Al Sharpton rides in and kicks the hornets nest.
Maybe it is a good idea for Hillary not to concede the nomination after-all?