2008 primary race. with the president s popularity ratings the lowest preconvention for any incumbent since the 1980s, the obama campaign knows the impact bill clinton could have. bill clinton loves to be needed as much as he needs to be loved. he is really needed by barack obama right now. reporter: tonight president obama will make his sales pih obam will make his sales pih rob, paula, the spe supposed tote. democrats were concerned the was a and that maybe people wouldn t show up. so they moved it inside to chance to see if he can get the same rethakts president clinton did last night. a big a tough act to follow, for sure. of course, president clinton talked a lot last night about his eight years in the white house, explain eopd how did he sell voters in that sense, in terms of re-electing the current president? rob, it was a deft sales pitch, and eight years at the