The Edwards campaign knows well the asset it has in Elizabeth Edwards, who’s more of a First Mom to America than Fred Thompson’s or Rudy Giuliani’s — or Hillary Clinton’s — mates. Today, they put out a video with her talking intimately, quietly at the camera — no crowds, no music. She just talks to us. And tries to make us feel guilty. Like a mom. She tells us we can’t wait to make a difference, join the campaign, change the world, all that. “The truth is, we don’t have all the time in the world.” Of course, those words have a different resonance coming from someone who is fighting incurable cancer.