Like Humphrey and Dukakis, Obama Goes After G.O.P. Running Mate

The Obama campaign is now apparently satisfied that Sarah Palin is a net liability for John McCain and that direct attacks on her won’t incur a backlash. But this is not the first time a Democratic campaign has come to this conclusion. Will Obama’s new ad be any more effective than those run by Michael Dukakis in 1988 or Hubert Humphrey in 1968?